Vaccinations for Animal Care Workers

J Am Assoc Lab Anim Sci. 2012 Sep; 51(5): 561–573.

Published online 2012 Sep.

Risk-Based Immunization Policies and Tuberculosis Screening Practices for Animal Care and Research Workers in the United States: Survey Results and Recommendations

Benjamin J Weigler

1Washington National Primate Research Center, Department of Comparative Medicine, and Department of Epidemiology, University of Washington, Seattle, Washington

Donna R Cooper

2Center for Comparative Medicine, Massachusetts General Hospital, Boston, Massachusetts (retired)

F Claire Hankenson

3University Laboratory Animal Resources and Department of Pathobiology, University of Pennsylvania, Philadelphia, Pennsylvania

Received 2012 Jan 17; Revised 2012 Feb 10; Accepted 2012 Apr 16.

Abstract

A national survey was conducted to assess immunization practices and tuberculosis screening methods for animal care and research workers in biomedical settings throughout the United States. Veterinarians (n = 953) were surveyed via a web-based mechanism; completed surveys (n = 308) were analyzed. Results showed that occupational health and safety programs were well-developed, enrolling veterinary, husbandry, and research staff at rates exceeding 90% and involving multiple modalities of health assessments and risk communication for vaccine-preventable diseases. Most (72.7%) institutions did not store serum samples from animal research personnel. More than half of the institutions housed nonhuman primates and maintained tuberculosis screening programs, although screening methods varied. Immunization protocols included various recommended or required vaccines that differed depending on job duties, type of institution, and nature of scientific programs. A single case of an identified vaccine–preventable illness in a laboratory worker was noted. Tetanus toxoid was the predominant vaccine administered (91.7%) to animal care and research workers, followed by hepatitis B (54.8%), influenza (39.9%), and rabies (38.3%). For some immunization protocols, an inconsistent rationale for administration was evident. Indications that animal care and research workers are unprotected from work-related etiologic agents did not emerge from this survey; rather, existing guidelines from the Advisory Committee on Immunization Practices and available biologics seem sufficient to address most needs of the laboratory animal research community. Institutions should commit to performance-based standards in parallel with context-specific risk assessment methods to maintain occupational health and safety programs and practices appropriate to their needs.

Abbreviation: ACRW, animal care and research workers; CDC, Centers for Disease Control and Prevention; IGRA, interferon γ release assay; OHS, occupational health and safety; PPD, purified protein derivative

Occupational health and safety (OHS) programs and practices in biomedical facilities that use animals in research, teaching, and testing vary greatly depending upon numerous factors, including the size and scope of the institution's scientific portfolio. For some institutions, the combination of infectious disease research and naturally occurring zoonotic agents within the experimental animals presents the possibility of biologic risks to animal care and research workers (ACRW) that greatly exceed those for the general public. 16,41,47 Herein, ACRW are defined as animal husbandry staff, veterinary technicians, veterinarians, research investigators, and any visitor, student, trainee, or other person, regardless of country of origin and primary residence (including laborers and maintenance workers), who come into direct contact with laboratory animals during the term of their activity in the workplace. The general-duty clause of the United States Occupational Safety and Health Act requires that places of employment be free from recognized hazards that are likely to cause death or serious physical harm, 31 whereas more detailed expectations exist for institutions to establish and maintain an OHS program as an essential part of their overall program of animal care and use. 10,20,29,30,33 Methods to demonstrate programmatic compliance with these OHS expectations have been published. 25,46

The identification of potential hazards in the work environment, the conduct of associated risk assessments, and the mitigation of risks associated with the experimental use of animals to acceptable levels, remain as the fundamental processes for the design of appropriate OHS programs in the laboratory animal research workplace. Biologic risk assessments are the responsibilities of laboratory directors and principal investigators, with Institutional Biosafety Committees, IACUC, biologic safety professionals, and laboratory animal veterinarians contributing expertise and guidance. 10 The conduct of informed biologic risk assessments requires the application of professional judgment, integrating a multitude of features and potential outcomes for the selection of appropriate safeguards without placing undue expense and burden on the institution for procedures that do not enhance safety. Estimates of the subjective uncertainty regarding each element of the risk assessment paradigm are essential for complete communication and undertstanding, 17,34 although this issue has largely been neglected in the laboratory animal science community. Uncertainty pertains to a lack of knowledge of the mathematical probability of events due to inherent errors of measurement, unclear cause–effect relationships, and a myriad of other factors, thereby impacting the reliability (that is, increasing or decreasing the degree of confidence) regarding the overall statement of risks and thus influencing the selection of strategies to manage them.

ACRW constitute a unique blend of persons (as outlined previously) for whom little specific risk-based data have been collected despite their plausible risk for infection with a variety of zoonoses and etiologic agents used in the conduct of animal research. 14-16,18,19,39,43,47 Persons designated as ACRW for purposes of inclusion within the institutional laboratory animal OHS program span several US Bureau of Labor Statistics occupational categories, 4 and this diversity prevents accurate interpretation of the published national and regional injury, illness, and fatality rate summaries. The population of at-risk ACRW is not monitored beyond the level of individual OHS institutional programs. Institutions adhering to the principles of the Guide for the Care and Use of Laboratory Animals (the Guide) have responsibility for critical ongoing self-regulation in determining the scope of their OHS programs, based on factors including the history of occupational illness and injury in the particular workplace, while remaining consistent with federal, state, and local requirements. 20 Targeted risk assessments for ACRW have been performed, 47 with the principal finding indicating a very low incidence of zoonotic diseases among ACRW employed in the United States. The annualized risk for persons in this area of employment was not different from that in livestock production and in healthcare services, arguably professions with broadly similar sets of daily tasks and exposure types. Although reassuring from the safety perspective, the rarity of occupationally acquired infection events among ACRW has limited quantitative risk assessment calculations for workplace exposure to etiologic agent hazards, as exist for some bloodborne pathogens in the human healthcare settings. 8,32 The spectrum of zoonotic disease agents of principle concern for persons who work in contemporary laboratory animal research have been reviewed, 1,2,14,15,18,19,29,30,40,41 but vaccines are not currently available for many of the frequently encountered agents (for example, B virus, Q fever, Chlamydophila, Pasteurella, Orf poxvirus).

The Guide recommends adoption of an appropriate vaccination schedule as one aspect of a comprehensive employee OHS program, including immunization of ACRW against tetanus. 20 Preexposure immunization for persons considered to have work-related risk of infection or exposure to specific agents such as rabies virus or hepatitis B virus also are noted, in addition to instances where research is to be conducted on infectious diseases for which effective vaccines are available. Recommendations for clinicians and other healthcare providers on immunization for 17 vaccine-preventable diseases that occur in infants, children, adolescents, or adults are provided without specific reference to ACRW. 6 Some additional federal guidance for immunization of ACRW notes that the "decision to immunize an employee should be made because of a clearly defined, recognized risk at the time of … health evaluations" and that one should make vaccines for hepatitis B, rabies, yellow fever, poliomyelitis, and tetanus available to "clearly identified at-risk employees." 29 These recommendations are to be followed with a medical doctor's oversight and in conjunction with the current adult vaccination schedules and practices described by the CDC. 9 ACRW who work with nonhuman primates are advised in reference materials to be vaccinated, at minimum, for poliomyelitis, rubeola virus, and rabies virus (for persons working in quarantine facilities for nonhuman primates), in addition to research-related agents. 1,28 Serious adverse events in young adults without known immunodeficiencies have been associated with at least one vaccine historically recommended as part of these programs. 42

Because of the longstanding effect of tuberculosis on nonhuman primates colony health and as a zoonotic agent for ACRW, 2,28 serial screening of nonhuman primates and their ACRW for this agent is an essential element of many OHS programs housing these species, in addition to screening of laboratory personnel where tuberculosis research is conducted. 10,21 The Guide and other references recommend that ACRW and others who may have contact with nonhuman primates or their tissues or body fluids should be screened routinely for tuberculosis. 1,20 Methods for tuberculosis surveillance noted in laboratory biosafety reference documents describe annual or semiannual skin testing with purified protein derivative (PPD) of previously skin-test-negative personnel. 10 Guidance on the correct use and interpretation of new interferon-γ release assays (IGRA), capable of differentiating tuberculosis infection compared with prior immunization with the attenuated vaccine strain Bacillus Calmette–Guérin, are provided by the CDC. 27

The Guide underscores the need for professional judgment in maintaining programs based on performance standards and refrains from prescription, beyond the listing of certain available vaccines. 20 Objective risk-based recommendations for tuberculosis 21,45 and for bloodborne pathogen prevention in human healthcare settings 8 already exist that follow population-based survey metrics. Similarly, OHS programs for ACRW will benefit from additional information that helps identify the nature and rationale for selecting different program elements, the incidence of vaccine-preventable illnesses in animal research environments, and tuberculosis screening methods and timelines.

Therefore, this survey was designed to assess features of OHS programs from a large, representative sample of biomedical research settings in the United States to provide current metrics on contemporary practices for comparisons within the context of regulatory guidelines and policies. To our knowledge, no previous study of this scale has been attempted. Our questions included risk perception regarding specific etiologic hazards to identify areas where additional information may be warranted. Another important designed outcome was to identify OHS program practices with the most variation between institutions with the intention of making recommendations toward a standard of care for this specialized subset of the general workforce.

Materials and Methods

Survey participants and enrollment.

Announcements about the development and purpose of the survey were made to laboratory animal veterinarians at professional gatherings (the 2008 AALAS National Meeting and the 2008 American College of Laboratory Animal Medicine Forum). The list frame for survey distribution was generated by combining the 2008 membership rosters of the American Society of Laboratory Animal Practitioners and American College of Laboratory Animal Medicine with duplicate names (n = 953 persons) purged. Subsequently, personalized letters of invitation were sent (February 2009) to all persons in the list frame via the US Postal Service to inform them of the purposes of the study (including funding sponsorship) and to encourage participation in the forthcoming web-based survey.

Because it was important for survey participants to have institution-wide knowledge of their animal care and use programs and associated occupational health components, only persons self-designated by the key filter question "Do you presently work as the attending veterinarian for laboratory animal care and use in at least one institution located inside the United States or its territories?" were included in the analysis. Participants were instructed to base their responses on the institution with the largest animal facility if they held the role of attending veterinarian at multiple entities.

Survey design and distribution.

The survey instrument was designed in close collaboration with Survey Research Operations, a unit of the Survey Research Center at the Institute for Social Research at the University of Michigan (Ann Arbor, MI). Survey Research Operations consultants oversaw and monitored all data collection activities and provided expertise in questionnaire development, programming, survey validation, data coding, and other elements necessary for study success. A Project Manager from Survey Research Operations was assigned to work closely with our research team to coordinate the daily aspects of data collection, management of participant emails, and distribution of reminder messages to nonresponders during the open survey period.

The draft survey consisted of 70 logic questions that linked to subject-focused follow-up questions based on the specificity of answers. Survey questions were written to allow multiple responses where indicated (such as animal species within the vivarium, categories of employees for OHS program elements, and others) and permitted open text responses for 'other' categories to allow for elaboration or opinion by individual respondents. The survey was pilot-tested among professionals (n = 5) with interest and experience in occupational health programs from public and private agencies. Suggestions from the pilot group were incorporated directly into the finalized survey, which then was administered as a web-based instrument.

Of the 959 survey invitation emails sent (March 2009), 102 (10.6%) were returned as undeliverable; therefore, invitation emails were resent to those persons with updated addresses, where available (56 of 102; 54.9%). Of those 56 repeat emails, 9 (16.1%) still did not reach the intended recipient. The invitation email contained customized passwords for website access and invitees were assured anonymity of their responses. The survey was accessible for 6 wk (03 March through 19 April 2009) through a secure personalized link maintained by Survey Research Operations on a computer file server. Responses were collated by Survey Research Operations, and information was coded without personal identifiers for individual respondents or their places of employment. Survey Research Operations monitored survey results daily and sent reminder email messages to nonresponders every other week for the open study period. Approval for the conduct of the survey was granted by the Institutional Review Boards for the University of Michigan and University of Pennsylvania.

Statistical methods.

Both quantitative and qualitative variables were obtained, retaining the coding from the web-based survey. Findings were tabulated and summarized by using descriptive statistics. Between-group comparisons were made by using a χ2 or Fisher exact test for categorical variables and with a 2-tailed t test or one-way ANOVA for continuous variables. A commercial statistical software package (SPSS Statistics Base Version 17.0, IBM, Armonk, NY) was used for comparisons, with a P value of less than 0.05 considered significant.

Results

The total number of survey respondents included 621 veterinarians (65.2% response rate). After filtering based on the key question of serving in the role of attending veterinarian (n = 311) and subsequently deleting responses (n = 3) where most questions were left unanswered, 308 remaining survey responses were available for analysis. Differences existed in the number of completed questions among respondents (for example, on topics specific to nonhuman primates for institutions lacking them within their animal census), so that some of the summaries tallied to fewer than 308.

Descriptive characteristics of surveyed institutions.

Most (49.4%) of responding attending veterinarians worked for academic institutions (Table 1), and next most common were attending veterinarian employed at pharmaceutical or biotechnology companies (18.8%). Approximately 88% (271 of 308) of the institutions at which respondents were employed were AAALAC-accredited. When cross-classified by categorical type, respondents' institutions did not differ significantly according to AAALAC accreditation status (Table 1).

Table 1.

Responding institutions by type and AAALAC-accreditation status

No. AAALAC-accredited No. not accredited Total (%)
Public academic institution 92 13 105 (34.1%)
Pharmaceutical or biotechnology company 46 12 58 (18.8%)
Private academic institution 42 5 47 (15.3%)
Contract research laboratory 21 3 24 (7.8%)
Nonprofit research organization or hospital 21 3 24 (7.8%)
Civil service 17 0 17 (5.5%)
Uniformed service 11 0 11 (3.6%)
Othera 12 1 13 (4.2%)
Research animal vendor 9 0 9 (2.9%)
Total 271 37 308 (100%)

The project purposefully allowed only one survey per attending veterinarian, with the specific request to base all responses on the veterinarian's place of employment with the largest animal facility. The expectation was that the larger facilities potentially would be the most programmatically diverse in terms of OHS needs, animal species used, and breadth of biomedical research. A broad variety of institutional sizes were reported (Figure 1). The distribution of respondents based on combined animal facility size was approximately Gaussian, with 60.1% (184 of 306) falling between 25,000 to 199,999 net square feet. This frequency distribution differed significantly (P < 0.0001) from that of all AAALAC-accredited institutions in the United States. Only 42.7% of AAALAC-accredited institutions during 2010 were classified within the facility size range of 25,000 to 199,999 net square feet. Therefore, the national distribution of AAALAC-accredited facilities includes proportionally a greater number of small facilities than did our sample.

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Distribution of institutional responses by facility size. nsf, combined net square footage of centralized and decentralized animal holding spaces.

Census of animals and their use in etiologic agent studies.

Responses affirmed census holdings of all laboratory animal species characterized within 28 grouped options on the survey (Table 2). As expected, mice, rats, and rabbits were present most commonly in animal facilities, whereas apes, marine mammals, and nonspecified collections of African and Asian Old World monkeys were least common. In addition to noting species present during the 12 mo prior to the survey, attending veterinarians were requested to note which of those were used in institutional research studies with etiologic agents capable of causing human infection at vertebrate Animal Biosafety Level 2 or higher. 10

Table 2.

Ranking of the most common research animal species used, including the percentage of institutions reporting each species grouping proposed for use in experimental infectious agent studies with the potential to cause human infection (at ABSL2 or higher)

Species groupings of animals No. of institutions using animals of indicated group (% of total institutions) Rank of use Some use of species group at ABSL2 or higher (%)
Laboratory mice of genus Mus 295 (95.8%) 1 69.3%
Laboratory rats of genus Rattus 289 (93.8%) 2 26.8%
Rabbits 234 (76.0%) 3 19.4%
Guinea pigs 185 (60.1%) 4 28.4%
Dogs 184 (59.7%) 5 6.0%
Swine 172 (55.8%) 6 17.5%
Fish 156 (50.7%) 7 5.8%
Macaques 153 (49.7%) 8 22.5%
Reptiles and/or amphibians 146 (47.4%) 9 2.1%
Hamsters 142 (46.1%) 10 32.6%
Other species of rodents 136 (44.2%) 11 28.2%
Birds and/or Fowl 118 (38.3%) 12 17.1%
Cats 106 (34.4%) 13 10.5%
Sheep 100 (32.5%) 14 9.1%
Ferrets 90 (29.2%) 15 34.8%
Goats 58 (18.8%) 16 7.0%
Cattle 57 (18.5%) 17 17.9%
Horses 45 (14.6%) 18 6.8%
Squirrel monkeys 33 (10.7%) 19 15.2%
Baboons 29 (9.4%) 20 6.9%
New World monkeys other than owl and squirrel monkeys 27 (8.8%) 21 3.7%
African green monkeys 26 (8.4%) 22a 42.3%
Bats 26 (8.4%) 22a 8.0%
Owl monkeys 12 (3.9%) 24 25.0%
Marine mammals 9 (2.9%) 25 0%
African Old World monkeys other than those listed previously 6 (2.0%) 26a 0%
Apes 6 (2.0%) 26a 8.3%
Asian Old World monkeys other than those listed previously 5 (1.6%) 28 40.0%

The greatest extent of biomedical research being performed above Animal Biosafety Level 1 was reported to occur in rodent species and various nonhuman primate species. Pooling all responses, 26 of the 28 species categories listed (92.8%) had reportedly been used in some degree of experimental infectious agent investigation involving work at Animal Biosafety Level 2 or higher.

Program enrollment for ACRW.

All respondents indicated that their institutions maintained an OHS program of some form. The percentages of institutions expecting staff participation in their OHS program, by job category, is shown in Table 3. More than 90% of programs enrolled their husbandry staff, veterinarians, veterinary technicians, and research investigators. Approximately 68% to 76% of programs enrolled maintenance workers, IACUC members, and trainees (for example, undergraduate and graduate students, postdoctoral fellows). Only visitors (on the premises for a single day or multiple days) were unlikely (16.0% to 41.5%) to participate in the OHS program at surveyed institutions.

Table 3.

Program goals for ACRW enrollment in OHS programs by job category

Job category or other role % OHS program enrollment goal
Husbandry staff 99.0%
Veterinary technicians 94.8%
Veterinarians 98.4%
Principal investigators 94.1%
Research technicians 94.1%
Maintenance personnel 76.1%
Postdoctoral fellows 72.2%
IACUC members other than listed previously 70.6%
Undergraduate or graduate students 68.3%
Environmental health personnel 67.3%
Multiday visitors 41.5%
One-day visitors 17.0%

Employee training for zoonoses and risk communication.

The mechanisms used by institutions for communicating health-related information and policy requirements regarding their OHS program, including the potential hazards of working with animals, varied greatly (Table 4). New-employee orientation sessions were the most common mechanism used to discuss specifics about vaccine-preventable illnesses for animal-related injuries and disease, followed by onsite in-person training, and lecture formats. Attending veterinarians (n = 46) who responded that other or additional mechanisms were used for OHS program communication noted the use of targeted health questionnaires (n = 3), information contained as part of the IACUC protocol approval process (n = 3), information provided during physical examinations (n = 6), and direct counseling by the institution's own occupational medicine department (n = 12), among others. Presence or absence of many of these communication mechanisms differed significantly (P < 0.05) when comparing AAALAC-accredited compared with nonaccredited institutions among respondents.

Table 4.

Risk communication methods used in OHS programs for vaccine-preventable illnesses at surveyed institutions

Type of risk communication % used overall
New employee orientation 72.2%a
On-site training by supervisor 69.6%
Lectures 65.7%
Handouts 58.8%a
Web-based learning 52.6%a
Conference attendance 16.7%a
Other 13.7%
No training provided after hiring 0.7%

Accessibility to occupational health clinics.

The majority (59.3%) of survey respondents were employed at institutions that provided occupational health clinical services in the same building or within a travel time of less than 15 min relative to the worksite. Services were available on the same campus but with a 15- to 45-min travel time at 37.4% of institutions. Travel to a different building or campus of greater than 45 min distance was necessary to receive services at 9.8% of institutions, whereas at 20.7% of institutions, occupational health professionals came directly to animal facility areas. Some programs had multiple options due to their size, complexity, and other nonspecific factors.

Types of OHS services provided.

Institutions used a myriad of health assessments to permit employees to work with research animals (Table 5). The top 3 medical assessments used by OHS programs, in descending frequency, included health history questionnaires, animal species exposure assessments, and immunizations. Given these frequencies, the percentages shown in Table 5 do not apply uniformly to all persons enrolled in the responding institutions' OHS programs; rather these data are provided for some proportion of the ACRW workforce per site.

Table 5.

Medical assessments and practices used by OHS programs to permit staff to work with animals

Type of medical assessment or practice No. using (%) Rank % requiring
Health history questionnaire 281 (92.1%) 1 94.3%
Animal species exposure assessment 235 (77.0%) 2 88.8%
Immunizations 224 (73.4%) 3 54.8%
Tuberculosis testing 215 (70.5%) 4 79.1%
Respirator fit testing 196 (64.3%) 5 54.7%
Serum evaluations for antibody titers or otherwise 133 (43.6%) 6 52.7%
Complete physical exam 108 (35.4%) 7 73.1%
Spirometry testing 102 (33.4%) 8 88.8%
Drug screening 86 (28.2%) 9 87.1%
Partial or targeted physical exam 77 (25.3%) 10 43.4%
Animal allergy testing 59 (19.3%) 11 15.3%
Other types of assessmentsa 50 (16.4%) 12 51.2%
No health assessments are performed 12 (3.9%) 13 not applicable

Serum storage.

Most (72.7%) institutions did not store serum samples from persons who work with research animals. However, serum was stored from a subset of ACRW at some institutions (17.1%) or, more rarely (5.9%), from all those working with research animals. Thirteen (4.3%) respondents were uncertain whether their institution maintained a serum storage program. These factors did not vary significantly according to the AAALAC-accreditation status of the institution but did differ (χ2 = 38.44, P = 0.03) according to the type of institution. Contract research laboratories (33.3%) and private academic institutions (29.8%) were most likely to have a serum storage program for their employees, whereas uniformed services institutions (9.1%) and pharmaceutical or biotechnology companies (12.7%) were least likely. Only 6 of the 70 (8.6%) responding institutions with serum storage programs affirmed that they had used some of the stored samples for medical evaluations or other purposes during the past 5 y. Four were private academic institutions, one was a pharmaceutical or biotechnology company, and one was from the uniformed services. Rabies (n = 5) and B virus (n = 4) were the most commonly cited etiologic agents included in the serum monitoring program.

Schedule of ACRW health reassessments.

Subsequent to their baseline occupational health assessments, most institutions (71.9%) remonitored their employees annually. Only 11.6% did so when experimental research programs changed, but 18.5% remonitored when employee duties changed or when there was a change in the involved species of laboratory animals. A small proportion of institutions indicated that they remonitored their employees semiannually (12.7%), and a similar proportion (13.4%) reported that reassessments were not done. Different circumstances and employee categories led to multiple types of reassessment frequencies at 45% of the institutions. The elements of remonitoring programs principally involved health history questionnaires (74.2%), tuberculosis testing (64.3%), animal species exposure assessments (51.5%), immunizations (46.0%), and additional respirator fit testing (49.5%). Drug screening (6.2%) and laboratory animal allergy testing (8.6%) were the least commonly used components of these reassessments.

For the most part (69.7%), environmental or occupational health office staff monitored the booster dates for any established immunization requirements, but in 15.8% of cases, persons were held responsible for monitoring themselves. Other monitoring mechanisms, if any, were not further delineated for the balance of responding institutions.

Tuberculosis screening programs.

Over half (51.9%) of surveyed institutions housed one or more species of laboratory nonhuman primates, and all of those had a tuberculosis screening program of some type for their workers, varying by job category (Table 6). The methodology for tuberculosis screening at most institutions was by PPD intradermal tuberculin skin testing alone (52.2%), followed by PPD skin tests in conjunction with symptom questionnaires (41.0%), and symptom questionnaires if a prior PPD skin test was positive (24.9%). Other mechanisms for screening included IGRA or radiographic tests or both (20%) and the use of symptom questionnaires alone (2.9%). Most institutions (78.5%) exempted persons previously vaccinated with Bacillus Calmette–Guérin from PPD skin testing, but exemption differed significantly (P = 0.015) according to type of institution, with public (22.7%) and private (43.6%) academic institutions least likely to exempt previously vaccinated persons. Persons exempted from PPD skin testing were most often tested by chest radiographs or other mechanisms (for example, IGRA; 85.4%) or symptom questionnaires (61.1%) or some combination thereof. Only 2 institutions did no further screening. A variety of tuberculosis screening programs existed at some institutions, so the combined frequencies totaled in excess of 100%.

Table 6.

Types of animal worker categories enrolled in tuberculosis screening programs

Category of animal care and research worker No. of institutions that enroll the described worker group in a tuberculosis screening program (%; total n = 304)
Maintenance staff 104 (34.2%)
Those working with any species of nonhuman primates 102 (33.6%)
IACUC members 100 (32.9%)
All persons regardless of their work with animal species 83 (27.3%)
Those working with tuberculosis research models other than nonhuman primates 51 (17.1%)
Visitors 48 (15.8%)
Only those working with Old World nonhuman primates 38 (12.5%)
Only those working with New World nonhuman primates 5 (1.6%)
Administrative staff 28 (9.2%)

Although 47.4% (146 of 308) of institutions did not have nonhuman primates in their census, some (n = 34) had a tuberculosis screening program for their ACRW nonetheless. A portion of these screening programs (n = 14) were done for ACRW exposed to experimental research on tuberculosis in animal models other than nonhuman primates, and the remainder were attributed across institution types (n = 6 were hospital settings) without further explanation. Therefore, the survey could not delineate what constituted institutional policy beyond a risk-based paradigm 21 or whether additional tuberculosis exposures that were not assessed motivated these programs.

The frequency of screening ACRW for tuberculosis varied principally between semiannually (53.5%) and annually (45.9%) among the programs (n = 157) responding to this question (Table 7). Our broad-based survey did not elucidate specific risk-based or other institutional motivations for the established tuberculosis testing scheme, including the extent to which they were intended to help protect the ACRW compared with protection of nonhuman primate colony health, where such colonies existed.

Table 7.

Frequency of tuberculosis testing for animal care and research workers in nonhuman primate areas

Type of institution More frequently than every 6 mo Every 6 mo Every year Total
Public academic institution 1 22 30 53
Private academic institution 0 13 24 37
Pharmaceutical/Biotechnology company 0 16 8 24
Contract research laboratory 0 14 4 18
Uniformed service 0 3 0 3
Civil service 0 6 0 6
Nonprofit research organization or hospital 0 3 4 7
Research animal vendor 0 3 0 3
Other type of institution 0 4 2 6
Total across institutions 1 84 72 157

In most cases, albeit in a little over half of the responses, the primary source for notifying persons that they were due for tuberculosis screening was a reminder sent by the institutional occupational health office (52%). Tuberculosis screening clinics regularly conducted by the occupational health group within facilities was another important mechanism (23.3%), followed by notification by animal facility managers (10.9%). At 2.5% of institutions, no system for notifying persons that they were due for tuberculosis screening existed and, at 1.5% of institutions, individual ACRW were held responsible for tracking their own tuberculosis screening timelines.

Of 203 responding veterinarians, 32 (15.8%) were aware of research animal worker(s) at their institution who had a positive skin test result for tuberculosis during the prior 5 y. The distribution of such cases differed significantly (P = 0.04) by type of institution, with most of those reports coming from private academic institutions (13 of 39 responding) and contract research laboratories (5 of 19 responding). Institutions were approximately evenly split on whether they allowed persons who were skin-test-positive for tuberculosis and who had clinically normal thoracic radiographs to work with nonhuman primates if they had not undergone isoniazid prophylaxis. At 34.8% of institutions, such persons would be allowed, at 33.6% of sites they would not be allowed, and the remaining 31.6% reported they would be allowed under some circumstances. No statistically meaningful differences existed for this factor by type of institution.

Conversion of research animals to a positive skin test for tuberculosis occurred at 26 of 273 (9.5%) institutions during the 5 y prior to survey; when details were provided, most of those occurrences were in rhesus and cynomolgus macaques (15 institutions), although squirrel and capuchin monkeys also were listed. Another 18 (6.6%) institutions did not know whether conversion of animals had occurred. No statistically meaningful differences existed for this factor by type of institution.

Immunization policies within OHS programs for ACRW.

Attending veterinarians were asked to report on the most common types of immunizations used within OHS programs (Table 8), including tetanus–diphtheria and tetanus–diphtheria–pertussis combination vaccines (91.7%), 24 hepatitis B (54.8%), influenza (39.9%), rabies (38.3%), and measles (32.0%) vaccines. The distribution of vaccines offered differed with respect to type of institution for 6 (tetanus, rabies, hepatitis A, influenza, measles, and yellow fever) of the 10 categories of vaccine type mentioned in the survey. These main findings overlap the general immunization recommendations for healthcare workers 6 and the general public (noting that measles, mumps, and rubella are formulated together as a single vaccine in the United States), 9 although inclusion of other vaccines (rabies, vaccinia, yellow fever, and experimental biologics) suggested that many OHS programs considered their ACRW at higher levels of occupational risk for some of these agents or that they felt obligated to include some of these vaccines in light of detailed notations in the Guide.

Table 8.

Types of immunizations recommended or required for research animal workers at surveyed institutions (n= 303)

Type of vaccine No. of institutions using the vaccine Rank of use
Tetanus toxoid-containing vaccine 278 (91.7%) 1
Hepatitis B virus vaccine 166 (54.8%) 2
Influenza virus vaccine 121 (39.9%) 3
Rabies virus vaccine 116 (38.3%) 4
Measles virus vaccine 97 (32.0%) 5
Hepatitis A virus vaccine 67 (22.1%) 6
Other type of vaccine 43 (14.2%) 7
Vaccinia (smallpox) virus vaccine 34 (11.2%) 8
Yellow fever virus vaccine 10 (3.3%) 9a
None 10 (3.3%) 9a

In addition to the immunizations listed, respondents from 43 of the institutions indicated a variety of other licensed and experimental vaccine products used occasionally within their OHP for ACRW. 11,38 These included anthrax vaccine (n = 10); tularemia vaccine (n = 7); vaccines for Japanese encephalitis, poliovirus, botulinum toxoid (n = 6 each); Venezuelan equine encephalitis virus (n = 5); Q fever (n = 4); Rift Valley fever virus (n = 3); typhoid vaccine (n = 2); meningococcal conjugate vaccine (n = 1); and other agents (n = 6). One or more such immunization products were used at institutions of all types (Table 9). Vaccinia (smallpox) virus vaccine was the most frequently cited specialized product used overall, particularly when this agent or portions of it were used for experimental purposes. 38

Table 9.

Expectations for special immunizations recommended or required for animal care and research workers

Occupational health program expectations for special immunizations (that is, other than tetanus, rabies, hepatitis A, hepatitis B, influenza, and measles virus)
Total
Type of institution None (%) One or more (%)
Public academic institution 89 14 (32.6%) 103
Private academic institution 38 9 (20.9%) 47
Nonprofit research organization or hospital 18 6 (14.0%) 24
Pharmaceutical or biotechnology company 52 4 (9.3%) 56
Contract research laboratory 21 3 (7.0%) 24
Other 10 3 (7.0%) 13
Civil service 14 2 (4.6%) 16
Uniformed service 10 1 (2.3%) 11
Research animal vendor 8 1 (2.3%) 9
Total 260 43 (100%) 303

Tetanus toxoid immunization programs.

Tetanus (which is formulated in combination with other agents such as diphtheria toxoid and pertussis) 9,24 was the most common vaccine administered to animal workers across all institutions. In most cases (49.3%), respondents indicated that recommendations for tetanus booster immunizations after an animal bite were made according to individual patient clinical backgrounds. However, many institutions (29.0%) apparently did not typically recommend this practice when the primary tetanus immunization series and booster doses were up to date. Overall, 18.0% of attending veterinarians indicated that booster immunizations usually were recommended to ACRW subsequent to a job-related animal bite regardless of the tetanus vaccination history. Booster recommendations after animal bites also varied depending on the species involved (Table 10), and 3.7% of institutions had no record of instances of animal bites. Of 274 responses to the question, 64.6% of respondents felt that ACRW at their institution were at the same relative risk of tetanus exposure as was the general public. Another 21.2% felt that their workers were at greater risk than was the general public, and 14.2% felt that they were at lesser risk. The most-cited reasons for respondents indicating a greater risk than the general public were attributed to their animal species and sources (43.1%), their experimental or diagnostic work (3.4%), the nature of their staff-community (1.7%), and a combination of those 3 factors (27.6%). Another 24.1% of respondents cited other reasons not listed among the options for response, including age (that is, physical condition) of animal facilities being a risk factor for tetanus exposure.

Table 10.

Likelihood of OHS programs (n = 49 respondents) that recommend a tetanus booster for animal care and research workers after a job-related animal bite

Source of bite Likelihood of recommendation Rank
Laboratory rodent 59.2% 1
Dog or cat 57.1% 2
Nonhuman primate 46.9% 3
Rabbit 44.9% 4
Any other large domestic animal 38.8% 5
Ferret 28.6% 6
Wild animal 24.5% 7
Domestic bird 6.1% 8
Reptile or amphibian 4.1% 9
Fish 2.0% 10

Rabies vaccination programs.

Serologic testing of ACRW for their antibody titers to rabies virus in lieu of rabies vaccine boosters was allowed at 83.8% of institutions, whereas 9.9% of institutions did not allow this provision; 6.3% of respondents were uncertain regarding their institutional policies on this topic. Of 115 responses to the question, 45.2% of respondents felt that ACRW at their institution were at the same risk of rabies exposure as was the general public. Another 34.8% felt that their workers were at greater risk than was the general public, and 20.0% felt that they were at lesser risk. The most-cited reasons for respondents indicating a greater risk than the general public were attributed to their animal species and sources (69.2%), their experimental or diagnostic work (15.4%), the nature of their staff community (4.0%), and a combination of those 3 factors (10.0%).

Hepatitis B vaccination programs.

Of 163 responses to the question, 60.7% of respondents felt that ACRW at their institution were at the same risk of hepatitis B virus exposure as was the general public. Another 30.7% felt that their workers were at greater risk than was the general public, and 8.6% felt that they were at lesser risk. The most-cited reasons for respondents indicating a greater risk than the general public were attributed to their experimental or diagnostic work (72.0%), their animal species and sources (14.0%), and a combination of those 2 factors (15.4%).

Hepatitis A vaccination programs.

Of 67 responses to the question, 68.7% of respondents felt that ACRW at their institution were at the same risk of hepatitis A virus exposure as was the general public. Another 23.9% felt that their workers were at greater risk than was the general public, and 7.5% felt that they were at lesser risk. The most-cited reasons for respondents indicating a greater risk than the general public were attributed to their animal species and sources (62.5%), their experimental or diagnostic work (31.3%), and the nature of their staff community (6.3%).

Influenza vaccination programs.

Of 121 responses to the question, 75.2% of respondents felt that ACRW at their institution were at the same risk of influenza virus exposure as was the general public. Another 21.5% felt that their workers were at greater risk than was the general public, and 3.3% felt that they were at lesser risk. The most-cited reasons for respondents indicating a greater risk than the general public were attributed to their experimental or diagnostic work (69.2%), the nature of their staff community (19.2%), and a combination of those 2 factors (11.5%).

Yellow fever vaccination programs.

Of 303 institutions responding to the question, the overwhelming majority (96.7%) of respondents did not offer yellow fever vaccinations to their ACRW, regardless of institution type. Of the 10 institutions that did vaccinate for yellow fever, 3 were public academic sites, 4 were private academic sites, and 3 were either uniformed or civil service entities.

Measles vaccination programs.

For 82.2% of institutions, their measles immunity program requirements or recommendations for ACRW were designed to protect their colonies of nonhuman primates, and 15.1% of institutions noted it existed for other reasons, such as general community health concerns, requirements of a research medical center, or as a consequence of measles-related research studies. Two respondents (2.7%) did not know why their occupational health program included programs to ensure staff immunity to measles virus.

OHS program review and immunization policy updates.

Overall, 73.9% of institutions had renewed or updated their vaccination recommendations for ACRW sometime during the 2 y prior to the survey, although a substantial proportion of attending veterinarians (17.2%) did not know when this issue had last been addressed. Although a variety of offices and persons held roles in the review process, institutional occupational health departments were most commonly (78.1%) responsible for maintaining and updating vaccination recommendations and requirements, followed by veterinarians (39.5%), environmental health or biosafety officers (28.8%), and institutional biosafety committees (19.3%). Animal care training staff (2.3%), the general counsel office (4.6%), and the human resource department (4.9%) were least likely to hold such responsibilities. In most cases (82.4%), veterinarians were considered active participants in the process of discussions and decisions regarding their immunization programs.

Financial support for OHS programs.

Institutions paid for all (75.5%) or at least some (10.1%) of the immunizations described and administered within their immunization programs for ACRW. In some cases (5.9%), investigators' budgets were required to fund such immunizations according to the specific research projects and associated risks. Surprisingly, some institutions (4.2%) required persons to arrange payment for their own vaccines, except as mandated by federal regulations for compliance with the OSHA bloodborne pathogens standard. 32 Other systems for cost reimbursement existed at the remainder of sites (4.2%), including using county health departments for vaccine services at no fee to the individual ACRW.

Episodes of vaccine-preventable diseases among ACRW.

Only one respondent (0.3%) was aware of a case of vaccine-preventable illness that had occurred in ACRW at their institution during the 5 y prior to the survey. In that instance, the worker apparently acquired ocular vaccinia virus after voluntarily declining vaccination before beginning laboratory work with the agent. The respondent reported that no changes to their institution's immunization policies and procedures resulted after that episode.

Resources used for OHS guidance and future needs.

A broad variety of professional resources were relied on for providing guidance toward the establishment of institutional immunization programs for ACRW. Most common sources by rank included occupational health physicians and nurses, the CDC, laboratory animal veterinarians at their institution and elsewhere, publications from the National Research Council's Institute for Laboratory Animal Resources, biosafety-related meetings and proceedings, AALAS publications, and recommendations and guidelines of the United States Advisory Committee on Immunization Practices. Other less commonly cited sources included research investigators, infectious disease physicians at academic medical centers, institutional biosafety officers, consultants, and local and state departments of health.

Only 36 of 296 (12.2%) of respondents felt there was presently an unmet need for specific vaccines within the scope of animal research at their institutions that would further improve the safety of those particular work environments. The balance of institutions (87.8%) did not feel that such unmet needs currently existed, and those proportions did not significantly differ by AAALAC-accreditation status or type of institution. The opinion of the attending veterinarian in regard to areas of additional guidance that would improve the design and conduct of immunization programs for their ACRW was provided (Table 11). Fewer than half of the respondents (42%) felt that sufficient guidance on immunization program design was currently available. However, many (38%) felt information was lacking regarding exposure assessment metrics for various types of practices and procedures in research animal settings.

Table 11.

Opinions of attending veterinarians regarding the need for additional professional guidance on aspects of risk assessment and the design and conduct of immunization programs for animal care and research workers

No. (%) of attending veterinarians that agreed with this statement Rank
No more guidance is needed for the appropriate design and conduct of immunization 127 (42%) 1
 programs for workers at my institution
More guidance is needed about the actual risks of exposure to vaccine-preventable hazards 115 (38%) 2
 for animal care and research workers
More guidance is needed about the infectious hazards caused by specific husbandry, 105 (35%) 3
 veterinary, and research procedures with animals
More guidance is needed about the risk reduction provided by specific types of safety 99 (33%) 4
 equipment, including personal protective equipment
More guidance is needed about determining the proficiencies of staff to conduct 48 (16%) 5
 procedures safely
More guidance is needed in other areasa 12 (4%) 6

Discussion

A comprehensive survey was designed and directed toward laboratory animal veterinarians to assess the scope and conduct of occupational health programs for ACRW at biomedical research and teaching facilities across the nation, particularly with respect to vaccination policies and tuberculosis screening. To our knowledge, no other comparable data set exists, despite its importance for benchmarking contemporary medical and ethical standards of practice, with important implications regarding regulatory compliance in animal care and use programs. The present study extends prior findings that animal research personnel in the United States are at low risk of occupationally acquired zoonotic diseases, given that only 1.7% of polled AALAS members had, in their opinion, been infected at their workplace over a 5-y period. 47 Thus, persons working with laboratory animal species had risks similar to those of employees of the agricultural livestock production and human health services industries, in terms of nonfatal occupational illness rates reported during 2002. Our survey responses suggested that OHS programs were well-developed at the majority of surveyed institutions, enrolling veterinary, husbandry, and research staff members at rates exceeding 90% and involving multiple modalities of health assessments and risk communication regarding vaccine-preventable diseases at their workplaces. As expected, immunization programs for research animal workers included a range of recommended or required vaccines that varied depending on the type of worker, type of institution, and nature of scientific programs. Only one respondent was aware of a case of vaccine-preventable illness (vaccinia) that had occurred in a laboratory worker at the respondent's institution during the 5 y prior to the survey.

Prophylactic immunizations are a component of core recommendations to provide protection for ACRW against infectious agents to which they may be occupationally exposed. 10 Most (91.7%) animal care personnel were vaccinated against tetanus, as recommended by the Guide 20 and by the Advisory Committee on Immunization Practices for all persons regardless of their type of employment. 6,9 Tetanus is caused by exposure of oxygen-poor tissues to tetanospasmin and tetanolysin, protein toxins produced by the spore-forming bacterium Clostridium tetani, which is found in soil and sometimes in human and animal feces. 24 Tetanus usually occurs after an acute injury, such as a puncture wound or laceration, with inoculation of the bacterial spore into tissues. 28 Immunization status is evaluated routinely after injury. 5,44 In laboratory animal facilities, both animals and equipment serve as hypothetical sources of exposure, although no reported cases of tetanus have been attributed specifically to patients working in these settings. 35 In contrast to those of livestock and other species, the intestinal tracts of laboratory mice and rats are poor hosts for C. tetani. 13,48 Regardless, 59.2% of institutions in our survey reported they would recommend a tetanus booster after a laboratory rodent bite, even without risk-based justification to warrant the practice.

The majority of tetanus cases in the general community occur among persons inadequately vaccinated or with unknown vaccination history who sustain an acute injury. 35 Adults, particularly farmers older than 50 y, are at highest risk. 37 As a corollary, tetanus vaccination may be most indicated for ACRW who work with large animals and in other settings of demonstrated risk, such as agricultural environments. Tetanus immune γ globulin is medically necessary for prevention of tetanus in nonimmunized and incompletely immunized persons with tetanus-prone wounds (for example, contaminated, necrotizing, or puncture wounds), and the administration of tetanus immune γ globulin is an essential, but often neglected, component of preventive wound care, even under circumstances of inadequate prior immunization. 5,44 Our survey did not identify factors that could increase the risk of tetanus exposure in research facilities above that of the general public, and in fact, 64.6% of responding institutions believed the risks to be equivalent, such that no modifications to the vaccination schedule recommended by the Advisory Committee on Immunization Practices for adults in general would be required. 9

CDC-based occupational indications for hepatitis B virus vaccination, supported by Occupational Safety and Health Administration standards, 32 include healthcare workers and public-safety workers who are exposed to blood or other potentially infectious body fluids. 8 Similarly, we found that 54.8% of institutions included hepatitis B in their immunization programs. Although most respondents (60.7%) felt their ACRW were at the same risk as was the general public, experimental and diagnostic work in the research setting was the principal reason (72.0%) for increasing the exposure risk at many (30.7%) locations. We did not survey for postvaccination antibody response, as has sometimes been the practice for healthcare workers considered at ongoing risk of occupational exposure. 6

Rabies vaccination policies differentiated ACRW personnel from other groups, with 34.8% of institutions perceiving them at greater risk than was the general public, and 20.0% felt that they were at lesser risk. Of 6154 rabid animals and 2 human cases of rabies reported to the CDC during 2010, none occurred in laboratory animal research settings, 3 possibly explaining the perceptions among some respondents of an occupational exposure risk less than that of the general community. Arguably, ACRW are in the infrequent risk category (greater than the population at large), given that any exposures would be episodic, with their source recognized and available for confirmatory testing. In this case, the primary vaccine course would be deemed sufficient, with no serologic testing or booster vaccine required. 7 Laboratory-acquired rabies is extremely rare. 43

Laboratory animal-associated influenza viral infections have not been reported, but there is possibility of human infection from experimentally infected ferrets. 10 A variety of human and animal strains of influenza virus are available for use in research, and large differences in the extent of protection provided by commercial vaccines can therefore be anticipated. Due to the nature of their staff community, 19.2% of institutions perceived their ACRW staff to be at increased risk for influenza exposure. Routine annual influenza vaccination is recommended for all persons 6 mo of age or older and, even if the exposures are community-acquired, substantial savings in direct medical costs and indirect costs from work absenteeism can result. 36 Notably, 33% of healthcare personnel surveyed indicated that they would reject influenza vaccination if they were required to pay for it. 36 Similar to our study, an internet-based survey of health professional schools in the United States 26 found that most schools now require vaccines recommended by the Advisory Committee on Immunization Practices for their students, with the caveat that proof of immunity is not required. Annual immunization for influenza was recommended at no charge to those health professional students, in part because unvaccinated personnel employed in the health care arena are at increased risk for transmitting vaccine-preventable diseases to their patients.

A measles vaccination or immunization verification program was provided at nearly a third of institutions surveyed for reasons of protecting personnel, animals, and the general community. Universal immunity of healthcare workers to measles has been long promoted, 23 and most nonhuman primates are susceptible to the agent. 22 Because of its public health importance, measles immunization is indicated by the Advisory Committee on Immunization Practices for all persons in the general community, regardless of their occupational exposure potential, with very select contraindications. 9

Several other licensed or investigational vaccines were used in 14.2% of responding institutions, some of which appeared to coincide with national biodefense and medical countermeasure priorities provided through the US Special Immunizations Program for laboratory personnel engaged in research with Select Agents. 11 Because accidents and containment failures can occur even in highly regulated environments with trained personnel, 40,41 the Special Immunizations Program currently offers a variety of investigational and licensed vaccine products to military and civilian personnel working in biohazardous environments who are considered to be at risk for pathogen and toxin exposure. Great reductions in the incidence of laboratory-acquired tularemia, Q fever, yellow fever, and Venezuelan equine encephalitis viruses—all agents with low infective doses—have been noted since the availability of such vaccines in research settings. 9

Removing administrative and financial barriers and providing vaccine in locations and at times easily accessible by staff has substantially improved vaccine acceptance and compliance with individual expectations of institutional OHS programs. We found that only 4.2% of ACRW were required to pay for the immunizations recommended or required of them by their OHS program. The burden of expenses for the ACRW vaccination programs, and for many other elements of OHS programs themselves, typically is incurred by a variety of institutional offices. We received open text survey comments suggesting that certain institutions may encourage vaccine coverage for their employees through their primary care providers outside of work. Others indicated that administrative support for OHS program participation at some institutions had not been provided consistently, in part due to concerns about financial burdens of regulations and oversight. The department from which an ACRW originates (for example, basic or clinical sciences departments for laboratory investigators and comparative medicine units for animal caregivers) frequently is held responsible for the costs of institutionally prescribed programs of occupationally related immunizations and tuberculosis screening.

Our survey revealed much variability in how institutions screen for tuberculosis, including the test methods used, the frequency of testing, and policies for ACRW access to nonhuman primates areas subsequent to positive tuberculin skin test or IGRA findings. Early and accurate detection, diagnosis, and reporting of cases leading to initiation and completion of treatment are essential principles for tuberculosis control. 21,45 Clearly, institutions have developed their programs to align with general guidelines and their own resources and experience. The broad spectrum of ACRW likely includes some persons who would be considered at high risk for tuberculosis infection. 21 The American Thoracic Society and the CDC specify criteria that define a positive tuberculin skin test result, with the intention of correctly identifying candidates for preventive therapy and minimizing the potential of unnecessary diagnostic evaluations or treatments in noninfected persons. 45

The US Food and Drug Administration has approved 2 commercially available IGRA for diagnosis of human infection with M. tuberculosis, and these assays are preferred in certain circumstances, such as for those persons previously vaccinated with Bacillus Calmette–Guérin. The CDC recently has updated their guidelines for usage of IGRA, noting that they may be used in all circumstances in which a tuberculin skin test is recommended, including patient contact investigations, evaluation of recent immigrants, and serial-testing surveillance programs for infection control (for example, in healthcare settings). 27 The costs and technical requirements for these IGRA tests is substantially greater than those for tuberculin skin testing, and each assay has different criteria for its interpretation, so that the results are not necessarily interchangeable. Cost-effectiveness studies are limited by the lack of critical data on the relative ability of these tests to predict subsequent disease. 27

Three tuberculosis screening risk classifications (low, medium, high) have been defined by the CDC to determine the frequency of tuberculosis testing for healthcare and laboratory workers that serve communities with a high incidence of tuberculosis. 21 Annual retesting after baseline screening is recommended for persons in the medium-risk category, which includes settings in which healthcare workers will be exposed to persons with tuberculosis disease or to clinical specimens that might contain M. tuberculosis. High-risk settings are considered those where potential ongoing person-to-person tuberculosis transmission is occurring, in which case retesting every 8 to 10 wk is recommended until the risk assessment has determined that the situation involving ongoing transmission has ceased. If uncertainty exists regarding whether to classify a setting as low or medium risk, the setting typically should be classified as medium risk. 21 Together, these factors indicate that the medium-risk classification parallels most nonhuman primate research settings. Because only very few occupationally acquired cases of tuberculosis among nonhuman primate workers have been reported, and none from our respondents, a principal motivation for tuberculosis surveillance programs is to protect the animals from infections originating from ACRW themselves. 1 Old World nonhuman primates are known to be more susceptible to tuberculosis mycobacteria than are New World species, 1,2,30 but our survey did not clearly differentiate that aspect in how institutions enrolled their ACRW in tuberculosis screening programs. However, tuberculosis research programs not using nonhuman primates, as well as institutions with patient-care settings, may have impacted the design of these programs beyond the extent captured in our survey.

The need for repeat skin testing should be determined by the likelihood of continued exposure to infectious tuberculosis. In certain environments, such as patient-care settings or nonhuman primate laboratory animal work, the exposure risk is sufficient to justify repeat testing at regular intervals. This survey found that institutions were evenly divided as to whether tuberculosis screening was done annually or semiannually. The frequency of repeat testing depends on the degree of risk for exposure, as determined by locally generated data, and screening programs should be reassessed regularly to determine their effectiveness. 21 Given the cost and time involved with tuberculosis skin testing, the rationale for semiannual screening should be made clear at each institution.

Programs of laboratory biosafety are relatively new to the broad field encompassed by OHS disciplines but nonetheless are essential for the protection of workers in clinical and research settings. Risk assessments contribute essential input to the design and refinement of effective biosafety programs, helping to guide selection of the appropriate biosafety level and microbiologic practices, safety equipment, and facility safeguards that can prevent occupationally acquired infections. The elements of complete risk assessments include: consideration of the number and severity of reported occupationally acquired infections; the infective dose for humans; the potential for exposure to infectious pathogens and toxins in conducting research protocols; results of studies to determine the number of microorganisms released into the air during common laboratory techniques; infection of cagemates by inoculated animals; excretion of the agent in urine, feces, and saliva of infected animals; any hazards peculiar to the animal species; and any increased susceptibility by sex. 10,11,28,29,43 Additional important considerations for personnel include: preexisting conditions among ACWR, in particular, compromised immunity due to HIV, cancer, or corticosteroid use; pregnancy or breast-feeding; personal medications; staff proficiencies regarding safe practices; the integrity of safety equipment; and the availability and use of specific therapies and effective preventive vaccines. The source and magnitude of uncertainty incorporated into components of risk assessment should be presented clearly alongside statements of risk to enable informed, scientifically justified regulatory decisions by policy makers. 34

Our comprehensive survey of immunization practices and tuberculosis testing programs for laboratory animal workers did not identify large deficiencies or deviations from current guidelines in the design and conduct of OHS programs that would increase the risk of workplace exposure to vaccine-preventable illnesses associated with animal research. However, the scope and nature of programs for tuberculosis testing varied widely by type of institution and species census holdings beyond clear parallels for screening programs in human healthcare settings. Veterinarians responding to our study perceived different levels of risk as compared with the general public to justify specific institutional vaccine requirements and recommendations in the absence of recorded infection transmission events. Therefore, one can presume that individual aspects of OHS programming were developed from a theoretical risk assessment framework.

Our survey documented that veterinarians actively participate in the decision-making regarding ACRW immunization programs and other OHS elements for their institutions. According to our findings and the supporting literature, we recommend that institutions invest continued intellectual capital in collaborative discussions to clarify and describe their approaches to vaccination and tuberculosis screening practices relative to hazard-based expected outcomes. Scheduled review of institutional policies and procedures, aligned with institutional experience of animal research-related accidents, injuries, and near-miss reports, should occur no less than annually (or when experimental research programs change) to ensure that programs are keeping pace with current recommendations for safe and efficacious preventive measures within the framework of risk assessments which are guided by the professional experts available to this field. 10,12

Employers have an ethical and legal mandate to follow best practices in biosafety in light of the hazards posed by the animals and materials used, including the provision of appropriate immunizations for persons at risk of infection or exposure to specific agents when effective vaccines are available. 10,11,22,29 Evidence that ACRW are unprotected from work-related etiologic agents did not emerge from this survey; rather, existing guidelines from the Advisory Committee on Immunization Practices and available biologics were sufficient to address most needs of the laboratory animal research community. Moreover, the differences between scientific programs and institutional size and resources, overlaid with current uncertainties regarding the actual risks and degree of exposure prevention provided by some procedures, warrant the structuring of OHS programs for ACRW at the institutional level, including input by veterinarians and health and safety specialists knowledgeable about the various intrinsic hazards of this field. Institutions should commit to performance-based standards in parallel with context-specific risk assessment methods to maintain OHS programs and practices appropriate to their needs.

Acknowledgments

Thank you to all of our ASLAP and ACLAM colleagues who provided responses to our survey. Funding for this work was provided by the ACLAM Foundation and the ER Griffin Research Foundation. We appreciate the consultation provided through the University of Michigan Survey Research Operations, particularly the extensive efforts of the Project Manager, Mr Andrew Hupp. Thank you to Ms Gineen Harris for arranging hardcopy invitation letters to surveyed institutions. Aspects of this work were presented to the laboratory animal science community at the ACLAM Forum (2011) and the National AALAS Meeting (2011).

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Vaccinations for Animal Care Workers

Source: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3447444/

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