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Rubella screening and vaccination follow-up by a hospital employee health office
Rubella screening and vaccination follow-up by a hospital employee health office H. W. Kohl III, M.S.P.H. Columbia, South Carolina
Rubella is usually a moderate and often asymptomatic infection in children and adults, but contraction of rubella virus by the susceptible woman during or prior to the early stages of pregnancy places the fetus at an increased risk of developing congenital defects. Cataracts, congenital heart disease, and partial or total deafness are the main manifestations of congenital rubella syndrome (CRS). 1 After the use of live attenuated rubella vaccines was approved in 1969, the thrust of vaccination programs in this country has been routine in prepubertal children and, to a lesser extent, selective in seronegative adult women. While this strategy has helped reduce rates of reported rubella, a curious cohort effect has occurred. Persons who were older than the optimal immunization age of 12 to 24 months in 1969 had less chance to obtain vaccination or to acquire natural immunity by contracting the disease. Moreover, the dramatic decline in the incidence of rubella during the early years of vaccine distribution allowed the unimmunized segment of the population to be protected via the herd immunity of the immunized people. It is in this cohort, now more than 15 to 18 years of age, that we observe the highest rate of rubella infection: in 1979 more than 70% of all reported rubella cases occurred in this age group? From the Department of Epidemiotogy and Biostatistics, School of Public Health, University of South Carolina. Reprint requests: H. W. Kohl, M.S.P.H., Institute for Aerobics Research, 12200 Preston Rd., Dallas, TX 75230.
124
From these observations it is safe to conclude that the potential for contracting and transmitting rubella in a health care facility setting is a very real problem, since a high proportion of hospital personnel fall within the susceptible age group. Several such outbreaks have been thoroughly documented74 These outbreaks place possibly pregnant seronegative women, employees as well as patients, and their fetuses at a high risk of r u b d l a and CRS. Because of these risks, the Advisory Committee on Immunization Practices has recommended that each hospital screen its employees for rubella antibody. To minimize these risks, a screening and immunization program was instituted at a county hospital in Central South Carolina in January 1982. The results of a study examining the extent to which the program has been able to maintain an ongoing and effective role in minimizing the likelihood of rubella infection in employees and therefore preventing employee to patient transmission of the rubella virus are presented herein. METHODS
The current screening and immunization program at this hospital, which serves a predominantly middle- to upper middle-class population, began January 1, 1982. At this time the program encompassed two phases. The first of these, the "catch-up" phase, is now complete; under it, hospital employees were screened on the first year's anniversary of their date of hire. In this manner the program was able to thor-
Volume 13 Number :3
Employee rubella screening
June, 1985
oughly screen all current employees within the period of 1 year. The second phase of the program began concurrently with the first phase, and it involves the screening of all new employees as they enter the payroll of the hospital. The population under consideration for the program consisted of all hospital employees. Personnel such as doctors, volunteers, clergy, and contract personnel (e.g., student nurses) are not considered employees of the hospital and are therefore not included in the program. The Employee Health Office (EHO) maintains current and o:rlgoing records regarding each individual screened for the presence of rubella antibody. Copies of serology reports as well as relevant demographic data for this population were made available either directly through the EHO or in cooperation with other administrative offices within the hospital. The interest in further characterizing the population subgroup with only negative serologies led to collection of information regarding date of birth, race, and sex. All of these data were made available through the EHO. Rubella hemagglutination inhibition antibody tests are performed in house by the serology laboratory of the hospital on all employees without written proof of prior vaccination. Susceptibility in a patient is defined by the hospital as a titer of less than 1 : 10. Copies of serology results are then forwarded to the EHO. Employees !Found to be susceptible to rubella virus are notified by the EHO of their susceptibility by letter, and an appointment with the employee health nurse is subsequently scheduled. In this conference the disease itself, its possible complications, as well as vaccination and its possible side effects are discussed. During this conference a signed consent form indicating either election or refusal by the employee to receive the vaccine is obtained and placed in his or her permanent file (Fig. 1). Regardless of the test results the hospital currently places no restrictions on where the employees may work in the hospital. Prior to October 1982, employees found to be susceptible to rubella virus and consenting to vaccination were referred by the EHO to the county health department (CHD), located near the hospital, to receive their vaccine. After Oc-
125
I NEW EMPLOYEE I I { Written Proof of Vaccination [ I
I
I
I
I
I INegative] I I Letter of Susceptibility I I ] Personal Discussion ] I [Consent to Vaccination] I
Fig. 1. Program for rubella screening of hospital employees.
tober 1982, however, all vaccines were offered in house through the EHO. Data regarding employee compliance in receiving the vaccine from CHD were obtained by a chart search at the facility.
RESULTS Of the 1585 total employee serology tests performed between December 20, 1981, and October 20, 1983, 95 demonstrated titers of less than 1"10. Therefore in the first 22 months of the program the susceptibility rate was determined to be 6%. A demographic characterization of this subpopulation showed several interesting results. In a breakdown by race, 87.4% of the seronegative employees were white, whereas 12.6% were nonwhite. Sex dichotomization shows a much larger proportion of women (86.3%) than men (13.7%). A further categorization into racesex groups essentially amplifies these findings. Of the female employees who were seronegative, 83.3% were white and 16.7% were non-
American Journal of
126 Kohl
INFECTION CONTROL
COMPLY YES NO HEALTH DEPT.
HOSPITAL
16 46 (25.8%) (74.2%)
62
(9631%)
1 (3.1%)
32 (100.0%)
47
47
(100.0~)
Fisher Exact p: 5.43 x 10" 12 Fig. 2. Improvement in compliance achieved through in-house vaccination program.
white. The male group, however, is represented by a deceptively small sample size (12 of 93 seronegative employees). The date on which each individual titer was drawn was available for 93 of the total 95 seronegative employees (97.9%). Coupled with each employee's date of birth, the age at which seronegativity was discovered was computed. No significant difference was noted either by race (white vs. nonwhite) or sex (p > 0.05). Both tests were performed using a pooled Student t test, assuming equal variances. Of the 62 seronegative employees referred to the CHD for immunization (prior to October 1982), only 16 (25.8%) complied with the referral and received the vaccine. There were no employees who complied with the referral but refused vaccination at the CHD. These numbers should be contrasted to the 31 of 32 employees (96.9%) who were referred for an in-house vaccination instead of to the health department (after October 1982) to receive the vaccine. Statistical comparison is almost a formality and shows a highly significant difference (Fig. 2); Fisher's exact test yields p < 10-12.
DISCUSSION This study shows a much lower rubella susceptibility rate among hospital employees than do other studies. Weiss et al. 5 reported the rate for hospital personnel in their study to be 20.1% and Polk et al? reported a rate of 12%. The rate of 6% found here, though attractive, remains without firm basis for explanation. One may
speculate that since the majority of the population under consideration are members of health professions, their motivation for personal risk reduction may be greater than that of the general population? This still leaves the differences stated here unexplained, however. The lack of an adequate comparison of the characteristics of seronegative employees with the rest of the hospital staff is an evident limitation of the study and is recognized as such. While it is strongly believed that there are no apparent differences between the seronegative employees and the rest of the hospital staff with respect to age, race, and sex characteristics, this assumption cannot be tested. Data regarding hospital employees as a group were not made available for this study. Given that a very large proportion of these hospital personnel are represented by younger age groups (Weathers P" Personal communication. 1983, West Columbia, S.C.), the age at which those who are susceptible are actually discovered to be seronegative should also have been relatively young. This, however, was not the case. Unexpectedly the mean age at which susceptibility was discovered in this population was relatively high (31.5 years). The most important implication of this study relates to employee compliance with the recommendation to receive vaccination. During the first months of the catch-up phase (from December 1981 to October 1982) seronegative personnel were referred to the local health department to receive their vaccinations. In the initial catch-up phase many tests, and consequently a proportionate number of seronegative titers, were expected. This expected load of work may have been the main factor in the decision to refer rather than to offer in-house vaccinations. There certainly are financial and personnel matters to consider. The consequences of referring seronegative employees to an outside agency (the CHD in this instance) for vaccination are reflected in the very low percentage of those complying with the referral to the CHD and actually receiving their vaccine (25.8%). Despite the nearby location of the CHD building, employee compliance for this time period was unacceptably low. The reasons f o r the low compliance rate of
Volume 13 Number :3
Employee rubella screening 1 2 7
June, 1985
those employees referred to the CHD are unclear. Certainly it is a strong contributing factor that even though the CHD facility is reached in less than a 5.-minute walk from the hospital, most of the referred employees may have considered it too much trouble to walk the extra distance for a nonmandatory vaccination. Another possible factor may be the probable clinic-type selEting of the CHD facility. Health care workers~ especially from a well-staffed, well-equipped facility, may be somewhat reluctant to enter a modest CHD facility for any type of treatment. It is difficult to safely assume that had the physicians, volunteers, and other contract personnel also been targeted in the rubella program, the rate of compliance with vaccination recommendation would have remained the same. Traditionally, hospitals have seen a tremendous difficulty in enrolling these types of personnel in 'voluntary vaccination programs. It may be suggested that the rate of compliance of the overall hospital population therefore might have been somewhat lower than that found in the target population. Conversely, the low susceptibility rate of the hospital employees may suggest certain intangible variables such as a high level of employee awareness and positive attitudes. If this is the case, it is believed that the rate of 96% is a realistic one that may be applied to the total hospital worker population. Given that the hospital no longer refers its employees to the CHD for vaccination, this experience should set a precedent for other institutions in planning and implementing or revising an employee rubella screening and immunization program. Clearly, referrals were not nearly as effective in reaching the target population as was an in-house program.
SUMMARY
The data in the present study indicate two major points. One is that the facility under question has an unusually low rate of rubella susceptibility. The other is that the referral of seronegative employees to an outside agency for vaccination (in this case the local CHD) is not nearly as effective, with respect to employee compliance, as an in-house program. Despite the added immediate cost to the hospital for administering the vaccine, the possibility of employee-to-patient transmission of the rubella virus poses the threat of a much higher future cost. It is suggested that facilities that do not currently have an in-house rubella vaccination program should reevaluate the effectiveness of their programs. Special thanks to Rona James and Jo Baker, R.N., of the Hospital Employee Health Office, and Pat Weathers, R.N., infection control nurse. Brian Butler aided in data collection. M. C. Weinrich, Ph.D., and C. A. Macera, Ph.D., gave constructive criticism on the manuscript.
Referen 9 1. Lamprecht C, Schauf V, Warren D, Nelson K, Northrop R, Christiansen M: An outbreak of congenital rubella in Chicago. JAMA 247:1129-1133, 1982. 2. Exposure of patients to rubella by medical personnel-California. MMWR 27:123, 1978. 3. Polk BF, White JA, DeGirolami PC, Modlin JF: An outbreak of rubella among hospital personnel. N Engl J Med 303:541-545, 1980. 4. Carne S, Dewhurst CJ, Hurley R: Rubella epidemic in a maternity unit. Br Med J 1:444-446, 1973. 5. Weiss KE, Falvo CE, Buimovici-Klein E, Magill JW, Cooper LZ: Evaluation of an employee health service as a setting for rubella screening and immunization program. Am J Public Health 69:281-283, 1979. 6. Chapell JA, Taylor MAH: Implications of rubella susceptibility in young adults. Am J Public Health 69:279281, 1979.
Rubella is usually a moderate and often asymptomatic infection in children and adults, but contraction of rubella virus by the susceptible woman during or prior to the early stages of pregnancy places the fetus at an increased risk of developing congenital defects. Cataracts, congenital heart disease, and partial or total deafness are the main manifestations of congenital rubella syndrome (CRS). 1 After the use of live attenuated rubella vaccines was approved in 1969, the thrust of vaccination programs in this country has been routine in prepubertal children and, to a lesser extent, selective in seronegative adult women. While this strategy has helped reduce rates of reported rubella, a curious cohort effect has occurred. Persons who were older than the optimal immunization age of 12 to 24 months in 1969 had less chance to obtain vaccination or to acquire natural immunity by contracting the disease. Moreover, the dramatic decline in the incidence of rubella during the early years of vaccine distribution allowed the unimmunized segment of the population to be protected via the herd immunity of the immunized people. It is in this cohort, now more than 15 to 18 years of age, that we observe the highest rate of rubella infection: in 1979 more than 70% of all reported rubella cases occurred in this age group? From the Department of Epidemiotogy and Biostatistics, School of Public Health, University of South Carolina. Reprint requests: H. W. Kohl, M.S.P.H., Institute for Aerobics Research, 12200 Preston Rd., Dallas, TX 75230.
124
From these observations it is safe to conclude that the potential for contracting and transmitting rubella in a health care facility setting is a very real problem, since a high proportion of hospital personnel fall within the susceptible age group. Several such outbreaks have been thoroughly documented74 These outbreaks place possibly pregnant seronegative women, employees as well as patients, and their fetuses at a high risk of r u b d l a and CRS. Because of these risks, the Advisory Committee on Immunization Practices has recommended that each hospital screen its employees for rubella antibody. To minimize these risks, a screening and immunization program was instituted at a county hospital in Central South Carolina in January 1982. The results of a study examining the extent to which the program has been able to maintain an ongoing and effective role in minimizing the likelihood of rubella infection in employees and therefore preventing employee to patient transmission of the rubella virus are presented herein. METHODS
The current screening and immunization program at this hospital, which serves a predominantly middle- to upper middle-class population, began January 1, 1982. At this time the program encompassed two phases. The first of these, the "catch-up" phase, is now complete; under it, hospital employees were screened on the first year's anniversary of their date of hire. In this manner the program was able to thor-
Volume 13 Number :3
Employee rubella screening
June, 1985
oughly screen all current employees within the period of 1 year. The second phase of the program began concurrently with the first phase, and it involves the screening of all new employees as they enter the payroll of the hospital. The population under consideration for the program consisted of all hospital employees. Personnel such as doctors, volunteers, clergy, and contract personnel (e.g., student nurses) are not considered employees of the hospital and are therefore not included in the program. The Employee Health Office (EHO) maintains current and o:rlgoing records regarding each individual screened for the presence of rubella antibody. Copies of serology reports as well as relevant demographic data for this population were made available either directly through the EHO or in cooperation with other administrative offices within the hospital. The interest in further characterizing the population subgroup with only negative serologies led to collection of information regarding date of birth, race, and sex. All of these data were made available through the EHO. Rubella hemagglutination inhibition antibody tests are performed in house by the serology laboratory of the hospital on all employees without written proof of prior vaccination. Susceptibility in a patient is defined by the hospital as a titer of less than 1 : 10. Copies of serology results are then forwarded to the EHO. Employees !Found to be susceptible to rubella virus are notified by the EHO of their susceptibility by letter, and an appointment with the employee health nurse is subsequently scheduled. In this conference the disease itself, its possible complications, as well as vaccination and its possible side effects are discussed. During this conference a signed consent form indicating either election or refusal by the employee to receive the vaccine is obtained and placed in his or her permanent file (Fig. 1). Regardless of the test results the hospital currently places no restrictions on where the employees may work in the hospital. Prior to October 1982, employees found to be susceptible to rubella virus and consenting to vaccination were referred by the EHO to the county health department (CHD), located near the hospital, to receive their vaccine. After Oc-
125
I NEW EMPLOYEE I I { Written Proof of Vaccination [ I
I
I
I
I
I INegative] I I Letter of Susceptibility I I ] Personal Discussion ] I [Consent to Vaccination] I
Fig. 1. Program for rubella screening of hospital employees.
tober 1982, however, all vaccines were offered in house through the EHO. Data regarding employee compliance in receiving the vaccine from CHD were obtained by a chart search at the facility.
RESULTS Of the 1585 total employee serology tests performed between December 20, 1981, and October 20, 1983, 95 demonstrated titers of less than 1"10. Therefore in the first 22 months of the program the susceptibility rate was determined to be 6%. A demographic characterization of this subpopulation showed several interesting results. In a breakdown by race, 87.4% of the seronegative employees were white, whereas 12.6% were nonwhite. Sex dichotomization shows a much larger proportion of women (86.3%) than men (13.7%). A further categorization into racesex groups essentially amplifies these findings. Of the female employees who were seronegative, 83.3% were white and 16.7% were non-
American Journal of
126 Kohl
INFECTION CONTROL
COMPLY YES NO HEALTH DEPT.
HOSPITAL
16 46 (25.8%) (74.2%)
62
(9631%)
1 (3.1%)
32 (100.0%)
47
47
(100.0~)
Fisher Exact p: 5.43 x 10" 12 Fig. 2. Improvement in compliance achieved through in-house vaccination program.
white. The male group, however, is represented by a deceptively small sample size (12 of 93 seronegative employees). The date on which each individual titer was drawn was available for 93 of the total 95 seronegative employees (97.9%). Coupled with each employee's date of birth, the age at which seronegativity was discovered was computed. No significant difference was noted either by race (white vs. nonwhite) or sex (p > 0.05). Both tests were performed using a pooled Student t test, assuming equal variances. Of the 62 seronegative employees referred to the CHD for immunization (prior to October 1982), only 16 (25.8%) complied with the referral and received the vaccine. There were no employees who complied with the referral but refused vaccination at the CHD. These numbers should be contrasted to the 31 of 32 employees (96.9%) who were referred for an in-house vaccination instead of to the health department (after October 1982) to receive the vaccine. Statistical comparison is almost a formality and shows a highly significant difference (Fig. 2); Fisher's exact test yields p < 10-12.
DISCUSSION This study shows a much lower rubella susceptibility rate among hospital employees than do other studies. Weiss et al. 5 reported the rate for hospital personnel in their study to be 20.1% and Polk et al? reported a rate of 12%. The rate of 6% found here, though attractive, remains without firm basis for explanation. One may
speculate that since the majority of the population under consideration are members of health professions, their motivation for personal risk reduction may be greater than that of the general population? This still leaves the differences stated here unexplained, however. The lack of an adequate comparison of the characteristics of seronegative employees with the rest of the hospital staff is an evident limitation of the study and is recognized as such. While it is strongly believed that there are no apparent differences between the seronegative employees and the rest of the hospital staff with respect to age, race, and sex characteristics, this assumption cannot be tested. Data regarding hospital employees as a group were not made available for this study. Given that a very large proportion of these hospital personnel are represented by younger age groups (Weathers P" Personal communication. 1983, West Columbia, S.C.), the age at which those who are susceptible are actually discovered to be seronegative should also have been relatively young. This, however, was not the case. Unexpectedly the mean age at which susceptibility was discovered in this population was relatively high (31.5 years). The most important implication of this study relates to employee compliance with the recommendation to receive vaccination. During the first months of the catch-up phase (from December 1981 to October 1982) seronegative personnel were referred to the local health department to receive their vaccinations. In the initial catch-up phase many tests, and consequently a proportionate number of seronegative titers, were expected. This expected load of work may have been the main factor in the decision to refer rather than to offer in-house vaccinations. There certainly are financial and personnel matters to consider. The consequences of referring seronegative employees to an outside agency (the CHD in this instance) for vaccination are reflected in the very low percentage of those complying with the referral to the CHD and actually receiving their vaccine (25.8%). Despite the nearby location of the CHD building, employee compliance for this time period was unacceptably low. The reasons f o r the low compliance rate of
Volume 13 Number :3
Employee rubella screening 1 2 7
June, 1985
those employees referred to the CHD are unclear. Certainly it is a strong contributing factor that even though the CHD facility is reached in less than a 5.-minute walk from the hospital, most of the referred employees may have considered it too much trouble to walk the extra distance for a nonmandatory vaccination. Another possible factor may be the probable clinic-type selEting of the CHD facility. Health care workers~ especially from a well-staffed, well-equipped facility, may be somewhat reluctant to enter a modest CHD facility for any type of treatment. It is difficult to safely assume that had the physicians, volunteers, and other contract personnel also been targeted in the rubella program, the rate of compliance with vaccination recommendation would have remained the same. Traditionally, hospitals have seen a tremendous difficulty in enrolling these types of personnel in 'voluntary vaccination programs. It may be suggested that the rate of compliance of the overall hospital population therefore might have been somewhat lower than that found in the target population. Conversely, the low susceptibility rate of the hospital employees may suggest certain intangible variables such as a high level of employee awareness and positive attitudes. If this is the case, it is believed that the rate of 96% is a realistic one that may be applied to the total hospital worker population. Given that the hospital no longer refers its employees to the CHD for vaccination, this experience should set a precedent for other institutions in planning and implementing or revising an employee rubella screening and immunization program. Clearly, referrals were not nearly as effective in reaching the target population as was an in-house program.
SUMMARY
The data in the present study indicate two major points. One is that the facility under question has an unusually low rate of rubella susceptibility. The other is that the referral of seronegative employees to an outside agency for vaccination (in this case the local CHD) is not nearly as effective, with respect to employee compliance, as an in-house program. Despite the added immediate cost to the hospital for administering the vaccine, the possibility of employee-to-patient transmission of the rubella virus poses the threat of a much higher future cost. It is suggested that facilities that do not currently have an in-house rubella vaccination program should reevaluate the effectiveness of their programs. Special thanks to Rona James and Jo Baker, R.N., of the Hospital Employee Health Office, and Pat Weathers, R.N., infection control nurse. Brian Butler aided in data collection. M. C. Weinrich, Ph.D., and C. A. Macera, Ph.D., gave constructive criticism on the manuscript.
Referen 9 1. Lamprecht C, Schauf V, Warren D, Nelson K, Northrop R, Christiansen M: An outbreak of congenital rubella in Chicago. JAMA 247:1129-1133, 1982. 2. Exposure of patients to rubella by medical personnel-California. MMWR 27:123, 1978. 3. Polk BF, White JA, DeGirolami PC, Modlin JF: An outbreak of rubella among hospital personnel. N Engl J Med 303:541-545, 1980. 4. Carne S, Dewhurst CJ, Hurley R: Rubella epidemic in a maternity unit. Br Med J 1:444-446, 1973. 5. Weiss KE, Falvo CE, Buimovici-Klein E, Magill JW, Cooper LZ: Evaluation of an employee health service as a setting for rubella screening and immunization program. Am J Public Health 69:281-283, 1979. 6. Chapell JA, Taylor MAH: Implications of rubella susceptibility in young adults. Am J Public Health 69:279281, 1979.