Determination of immune status to measles, rubella, and varicella-zoster viruses among medical students: assessment of historical information

A global perspective of vaccination of healthcare personnel against measles: systematic review

Measles transmission has been well documented in healthcare facilities. Healthcare personnel who are unvaccinated and who lack other evidence of measles immunity put themselves and their patients at risk for measles. We conducted a systematic literature review of measles vaccination policies and their implementation in healthcare personnel, measles seroprevalence among healthcare personnel, measles transmission and disease burden in healthcare settings, and impact/costs incurred by healthcare facilities for healthcare-associated measles transmission. Five database searches yielded 135 relevant articles; 47 additional articles were found through cross-referencing. The risk of acquiring measles is estimated to be 2 to 19 times higher for susceptible healthcare personnel than for the general population. Fifty-three articles published worldwide during 1989-2013 reported measles transmission from patients to healthcare personnel; many of the healthcare personnel were unvaccinated or had unknown vaccination status. Eighteen articles published worldwide during 1982-2013 described examples of transmission from healthcare personnel to patients or to other healthcare personnel. Half of European countries have no measles vaccine policies for healthcare personnel. There is no global policy recommendation for the vaccination of healthcare personnel against measles. Even in countries such as the United States or Finland that have national policies, the recommendations are not uniformly implemented in healthcare facilities. Measles serosusceptibility in healthcare personnel varied widely across studies (median 6.5%, range 0-46%) but was consistently higher among younger healthcare personnel. Deficiencies in documentation of two doses of measles vaccination or other evidence of immunity among healthcare personnel presents challenges in responding to measles exposures in healthcare settings. Evaluating and containing exposures and outbreaks in healthcare settings can be disruptive and costly. Establishing policies for measles vaccination for healthcare personnel is an important strategy towards achieving measles elimination and should be a high priority for global policy setting groups, governments, and hospitals.

Validity of self-reported vaccination status among French healthcare students

Data on validity of self-reported vaccinations are scarce. This study, performed on healthcare students in Paris (France), aimed to evaluate this validity for occupational vaccinations. The validity of self-reported vaccination status was compared with written information. A total of 432 students were enrolled. Sensitivity rates for BCG, hepatitis B and measles were over 74%. For diphtheria-tetanus-polio and pertussis, sensitivity was below 50%. Specificity was between 70 and 95% for dTP-pertussis, and below 35% for all others. Overall, the validity of self-reported information was low, meaning that checking medical records remains the preferable strategy for assessing immunization status.

Vaccine knowledge in students in Paris, France, and surrounding regions

INTRODUCTION

In France, young adults are legally freed from parental authority at the age of 18 years and are, thus, responsible for their own vaccine record. This young adult population is more frequently exposed to vaccine-preventable infectious diseases.

OBJECTIVE

To determine the factors associated with students' knowledge of the interval between two antitetanus boosters and their report of having up-to-date vaccinations.

METHODS

In April 2009, a survey was conducted involving a random sample of students between 18 and 25 years of age eating lunch at university dining facilities in Paris and its suburbs (Ile de France).

RESULTS

Among the 677 students approached, 583 agreed to participate. Only 207 (36%) of respondents knew the recommended dosing interval between two doses of tetanus vaccine booster (10 years). The majority of students (69%) reported having up-to-date vaccinations. Declaring having up-to-date vaccinations was significantly associated with having a general practitioner (OR 3.03 [95% CI 1.69 to 5.55]). Health care students were significantly more likely to know the decennial interval between two antitetanus boosters (OR 2 [95% CI 1.28 to 3.25]). Most of responding students (n=519 [89%]) believed that vaccines were very useful.

CONCLUSIONS

An overall lack of knowledge of vaccines was observed among this student population. Health care providers, such as GPs and university medical practice staff, who interact with these young individuals have an essential role to promote better vaccination coverage in this population.

Vaccination and screening of medical students: results of a student health initiative

OBJECTIVE

To evaluate the immune status and vaccination needs of first-year medical students in relation to bloodborne viruses and common vaccine-preventable diseases.

DESIGN, SETTING AND PARTICIPANTS

Survey of first-year medical students at the University of New South Wales, Sydney, NSW, attending a mandatory screening and vaccination clinic, 2002-2005.

MAIN OUTCOME MEASURES

Self-reported history of vaccination or natural infection; serological evidence of immunity to measles, mumps, rubella and varicella (presence of specific IgG) and hepatitis B (presence of hepatitis B virus surface antibodies) or infection with hepatitis B and C viruses and HIV; and Mantoux test results.

RESULTS

733 students attended the clinic (85% of those enrolled). Four students were positive for HBsAg and four had hepatitis C antibodies. None were HIV-positive. Twenty-nine per cent (216/733) were not immune to hepatitis B, 33% (238/724) to mumps, 26% (190/724) to measles, 13% (91/724) to rubella and 10% (75/724) to varicella. About 23% (91/237) needed further testing for tuberculosis. Immunity corresponded poorly with self-reported history of vaccination. More students reported vaccination against rubella (96%), measles (81%) and mumps (80%) than were immune, and fewer reported vaccination against hepatitis B (44%).

CONCLUSIONS

Many students were not immune to vaccine-preventable diseases, and a small number had a previously undiagnosed bloodborne virus infection (hepatitis B or C). The level of immunity to vaccine-preventable infections was unacceptable and justified the provision of an easily accessible program for screening and vaccination.

Reliability of medical students' vaccination histories for immunisable diseases

BACKGROUND

Medical students come into contact with infectious diseases early on their career. Immunity against vaccine-preventable diseases is therefore vital for both medical students and the patients with whom they come into contact.

METHODS

The purpose of this study was to compare the medical history and serological status of selected vaccine-preventable diseases of medical students in Germany.

RESULTS

The overall correlation between self-reported medical history statements and serological findings among the 150 students studied was 86.7 %, 66.7 %, 78 % and 93.3 % for measles, mumps, rubella and varicella, conditional on sufficient immunity being achieved after one vaccination. Although 81.2 % of the students' medical history data correlated with serological findings, significant gaps in immunity were found.

CONCLUSION

Our findings indicate that medical history alone is not a reliable screening tool for immunity against the vaccine-preventable diseases studied.

Seroprevalence and immunization history of selected vaccine preventable diseases in medical students

To evaluate protection against vaccine-preventable diseases in medical students, we obtained data on immunization status and history of diphtheria, tetanus, pertussis, poliomyelitis, measles, mumps, rubella, varicella and hepatitis B from students with elective periods in our institution. Further, serum antibodies against measles, mumps, rubella and varicella-zoster virus (VZV) and hepatitis B surface (HBs) antigen were determined on a voluntary basis. For students with incomplete immunization status or lack of protective antibodies, vaccination was offered for free. Success of catch-up immunizations was serologically confirmed 4 weeks later. From May 1999 to April 2003, 170 students were enrolled; their mean age was 26 years with a median of 25 years (range 22-48 years). Immunization records were complete in 148 (87%), incomplete in 11 (6.5%) and missing in 11 (6.5%) students. Only 26% of the cohort had a complete and up-to-date immunization status. Seroprevalence of IgG antibodies against measles, mumps, rubella, VZV and HBs (> or = 10 IU/l) in 149 students were 85, 85, 92, 97 and 90%, respectively. Indications for > or = 1 catch-up immunization were found in 125 (74%) students and were accepted by 97 of them (78%). Sixty two (99%) of 63 immunized students available for follow-up demonstrated an adequate serological response. In conclusion, the great majority of medical students had immunization gaps. Systematic immunization programmes for medical students should be implemented.

Systematic review of the literature on postpartum care: selected contraception methods, postpartum Papanicolaou test, and rubella immunization

BACKGROUND

The postpartum period is a time when many routine interventions are provided to mothers. This review examined the published evidence for the effectiveness of selected contraceptive methods, Papanicolaou (Pap) tests, and rubella immunization.

METHODS

MEDLINE, Cinahl, PsycINFO, and the Cochrane Library were searched for randomized controlled trials of interventions initiated from immediately after birth to 1 year in postnatal women. The initial literature search was done in 1999, and was enhanced in 2003. Studies were categorized and reviewed by topic areas. Data were extracted in a systematic method, and the quality of each study was reviewed.

RESULTS

In the 1999 search, 140 studies were randomized controlled trials that met the selection criteria: 5 related to postpartum contraception, 1 to timing of the postpartum Pap test, and 2 to postpartum rubella immunization. In the 2003 searches, 1 additional study related to postpartum contraception was identified. From the published literature on selected contraceptive methods, the intrauterine devices examined were effective in preventing pregnancy and had comparable side effect profiles. No clear recommendation can be made because insertion timing was not randomized in the included trials. Although delaying the postpartum Pap smear until 8 weeks reduces the proportion of inflammatory smears, it is uncertain whether a Pap smear is of benefit to postpartum women. The RA 27/3 postpartum rubella vaccine appears to be more effective than the Cendehill vaccine, but a small proportion of women may develop acute and chronic joint manifestations.

CONCLUSIONS

Some evidence is available to support selected postpartum contraceptive methods and the postpartum rubella vaccine, but data are lacking on the effectiveness and optimal timing of the postpartum Pap smear.

How reliable is the history of chickenpox? Varicella serology among children up to 14 years of age

OBJECTIVES

The aim of this study was to assess the seroprevalence of antibodies to varicella-zoster virus (VZV) in children of northern Greece and to estimate the reliability of varicella history.

METHODS

A serosurvey of 632 children, aged 13 months to 14 years (median 5.2 years), was conducted between April 1999 and July 2001. Serum samples were tested by enzyme-linked immunosorbent assay (ELISA) for IgG antibodies to VZV (IgG Genzyme Virotech GmbH). A history of varicella in these children was obtained from the parents of all these patients. Also, a check of state health cards of the patients was done.

RESULTS

Two hundred and forty-eight (39%) of the children were seropositive for VZV. Two hundred and thirty (36%) of the 632 children claimed to have had previous varicella infection; 87.8% were seropositive, and 12.2% lacked antibodies to VZV. One hundred and seven of the 230 children with a history of varicella had the information about the disease confirmed, as it was reported on their state health card by a pediatrician; 10.2% were seronegative for VZV. Absence of history of varicella was reported in 402 (63.6%) of the 632 children; 88.6% of those were seronegative, and 11.4% were seropositive. The percentage of incorrect negative history ranged from 6% (13-60 months of age) to 48% (120-168 months of age).

CONCLUSIONS

A large proportion of the study group (61%), mainly below 7 years of age, is susceptible to varicella. The positive predictive value of a history of varicella is 87.8%, whereas the negative predictive value of a negative history is 11.4%, which means that there is an 88.6% probability of a negative history being correct. Varicella serology may be reasonable prior to vaccination in children >10 years old with a negative chickenpox history. However, if one excludes cost considerations, it is also reasonable to vaccinate all children, irrespective of serostatus.

Prevalence of serological markers against measles, rubella, varicella, hepatitis B, hepatitis C, and human immunodeficiency virus among medical residents in Mexico

BACKGROUND

Vaccination programs among health care workers are based on seroprevalence studies, which seldom include medical residents or students. The objective of this study was to determine the seroprevalence of antibodies against measles, rubella, varicella, hepatitis B (HBV), hepatitis C (HCV), and human immunodeficiency virus (HIV) among medical residents.

METHODS

This study was designed as a prospective survey. A self-reported questionnaire was used to obtain the information. Serum samples were tested for antibodies by commercial immunoenzymatic assays. Statistical analysis was descriptive; history of exposure was evaluated as a diagnostic test and sensitivity, specificity, and predictive values were calculated according to Bayes theorem.

RESULTS

Eighty-nine residents were included, the median age was 27 years, and 58 (65.2%) were female. Seventy-two (79.7%) had been vaccinated against HBV, but vaccination was complete in only 30/72 (41.6%). All were positive for measles and varicella, with the exception of one case for each. The serology for rubella was negative in 12 residents (10 women). Three residents had anti-core against HBV, with negative surface antigen. One positive case for HCV was confirmed by Western blot. All were negative for HIV. A history of prior varicella had a 100% positive predictive value; in contrast, the negative predictive value was quite low (7%).

CONCLUSIONS

Negative serology for rubella among women and incomplete vaccination against HBV support the implementation of vaccination programs in medical schools in Mexico.

Seroprevalence of varicella antibodies among new house officers

STUDY OBJECTIVE

Varicella, an illness common to children, can occur in nonimmune adults, often causing serious morbidity and mortality. House officers without protective titers to varicella are at risk of contracting the disease and may spread it to the patients they serve. They are also subject to significant losses in work time and wages. Accordingly, in August 1996, the Centers for Disease Control and Prevention recommended vaccinating nonimmune health care providers with the varicella vaccine. We also sought to document the seroprevalence of varicella antibodies among new house officers and to determine the association of self-reported history of infection with varicella antibody levels.

METHODS

This study was conducted at a university-affiliated teaching hospital. Serology testing was performed on house officers beginning their residencies in July 1997. Subjects provided information regarding demographics, medical history, previous varicella exposure, and previous administration of varicella vaccine. Serum was tested using the FIAX test kit, (Biowhitaker, Walkersville, MD).

RESULTS

One hundred fifty-four house officers participated. The mean age was 30 (range, 24 to 50+/-SD 5.5 years). History of varicella infection was given by 119 (77%) of the 154 subjects, whereas 15 (10%) reported no history of infection, and 20 (13%) were uncertain. Ten (7%) of the participants had received varicella vaccine previously. Overall, 6 (4%) had nonprotective titers to varicella. Of the 119 house officers who reported a history of varicella, only 2 (1.7%) had nonprotective titers, and 4 (27%) who reported no history of varicella infection had nonprotective titers. Of the 10 house officers who had previously received varicella vaccine, 1 (10%) had nonprotective titers.

CONCLUSION

Although most house officers had protective titers, a reported history of varicella or the administration of varicella vaccine did not assure the presence of protective titers. House officers should be tested for varicella immunity regardless of a history of previous infection or the administration of varicella vaccine.

Immunoglobulin M antibody response to measles virus following natural virus infection, primary vaccination, and reexposure to the virus

Evaluation of the measles virus ELISA kit (Merck) to detect specific IgM as an indicator of primary measles antibody response was carried out. A modification of the manufacturer's cutoff value interpretation was introduced to allow for equivocal results in addition to positive and negative ones. With this modification, the test assayed gave an overall reproducibility of 96.16%. The IgM seropositivity rate for seroneutralization-confirmed measles cases was 100% for naturally infected measles subjects and 90% for primary measles vaccinated subjects. Individuals with positive neutralizing antimeasles antibodies in close contact with a confirmed measles case gave the following measles IgM ELISA results: 54.54% negative, 9.09% positive, and 36.36% equivocal, showing a booster with IgM antibody response on reexposure to the virus. Positive subjects with neutralizing antimeasles antibodies without recent contact with a measles case gave negative IgM results. IgM seropositivity was strongly associated with IgG seroconversion and clinical measles (p < 0.0001). The technique assayed performed adequately for the confirmation of both measles natural infection and primary vaccination and for the differentiation of primary and secondary antibody response, taking into account the modification in the cutoff value interpretation introduced and providing that the serum samples are obtained between days 5 and 30 after onset of rash.

Immunization requirements for pharmacy students

OBJECTIVE

To identify current immunization requirements for pharmacy students throughout the US.

DESIGN

Self-administered questionnaire.

SETTING

Seventy-five colleges and schools of pharmacy in the US.

MAIN OUTCOME MEASURES

Immunization policies, immunologic requirements, timing of vaccination in relation to the beginning of clerkship experience, payment, mechanism to revise policies.

DATA ANALYSIS

Descriptive statistics.

RESULTS

Overall, 57 programs (81 percent) have an immunization program in place, but 13 programs (19 percent) have no immunization program. More than 50 percent of the colleges or schools reported requiring that pharmacy students have measles, mumps, rubella, tetanus, and purified protein derivative of tuberculin (PPD) vaccinations upon entry of clerkship. Only 25 college or schools of pharmacy (44 percent) required students to have the hepatitis B vaccine and 8 (14 percent) to have a PPD evaluation upon completion of clerkship experience. Responsibility for the immunization program was shared evenly between the clerkship coordinator and the student health clinic. Approximately 65 percent of programs maintain an immunization record on file for each student. Completion of immunizations was required in 36 schools (64 percent) before entering clerkship activities, 15 (26 percent) before entrance to the professional program, and 3 (5 percent) in the first year of the program. Six schools (11 percent) had a program in place for less than one year, 27 (47 percent) between one and five years, and 24 (42 percent) for more than five years. At the majority of schools, students are responsible for the cost of immunization.

CONCLUSIONS

Most schools of pharmacy do not adhere to the specific immunization recommendations described by the Centers for Disease Control and Prevention for healthcare workers. Pharmacy schools need to reexamine their immunization policies and update them to reflect the most current standards. We suggest a policy for immunization of pharmacy students.

[Are medical students sufficiently vaccinated? Results of a serological survey and of vaccine coverage]

A total of 143 medical students participated in a serological and immunization coverage survey in Geneva. Between 29 and 54% had not received the 6 injections recommended in Switzerland against tetanus, diphtheria and poliomyelitis. The vaccination rates remain low against measles (57%), rubella (46%) and mumps (11%). Satisfactory levels of antibodies against measles were detected in all students. Between 4 and 6% did not have antibodies against mumps, varicella and rubella. Only 5.4% of Swiss medical students had antibodies against hepatitis A. HBc antibodies were present in 4% of the students. Medical students are at risk of contracting and transmitting vaccine preventable diseases. Swiss medical schools should play a leading role in the development of screening programs encouraging immunization of students entering university.

The risk of measles, mumps, and varicella among young adults: a serosurvey of US Navy and Marine Corps recruits

OBJECTIVES

To assess the risk of epidemic transmission and to guide immunization policy, the seroprevalence of antibody to measles, mumps, and varicella was determined in a group of young adults.

METHODS

A cross-sectional study of 1533 US Navy and Marine Corps recruits was conducted in June 1989. Antibody status was determined with commercially available enzyme-linked immunosorbent assays.

RESULTS

Direct sex and race adjustment to the 15- to 29-year-old US population resulted in seronegativity rates of 17.8% for measles, 12.3% for mumps, and 6.7% for varicella. Measles and mumps seronegativity rates were higher among Whites whereas varicella seronegativity was higher among non-Whites. Recruits enlisting from outside the 50 US states, especially those from island territories, were more likely to lack varicella antibody. The sensitivity of a positive history of vaccination or disease in predicting antibody status was less than 90% for all diseases.

CONCLUSIONS

These results suggest a continued potential for epidemics, especially of measles, and the need for mandatory immunization policies. Immigrants to the United States, especially those from island territories, may be a high-risk group that could benefit from varicella vaccination.

Secondary immune response in a vaccinated population during a large measles epidemic

The rates of secondary immune response (SIR) and secondary vaccine failure (SVF) during a measles epidemic (10,184 notifications) were evaluated. A patient with SIR was defined as a subject for whom all sera were immunoglobulin G (IgG) positive and IgM negative with a significant increase in complement fixation titer. A patient with SVF was defined as a vaccinated symptomatic subject showing a SIR. Sequential sera from 898 subjects were tested for measles antibody by enzyme-linked immunosorbent assay (IgG and IgM) and by complement fixation. Evidence of recent anti-measles virus specific immune response was found in 496 subjects (55.5%). The vaccination rate was estimated at 74.6% (99% confidence interval [CI], 67.9 to 80.7%). The number of exposed vaccinated subjects was estimated at 370 (74.6% of 496). The SIR rate was 4.03% (20 of 496) (99% CI, 2.1 to 6.9%) among subjects with immune response. These 20 subjects were 2 with measles (Centers for Disease Control's definition), 6 with measles with rash of unknown duration, 8 with presumed measles with either rash or fever, 3 asymptomatic subjects (2 with recent contact with a measles case), and 1 undocumented subject. Since 3 patients with SIR were asymptomatic and 2 others were documented as not vaccinated, there was a maximum of 15 probable occurrences of SVF among the 20 patients with SIR. The SVF rate among exposed vaccinated subjects was estimated at 4.05% (15 of 370) (99% CI, 1.9 to 7.5%). In conclusion, neither prior vaccination nor detectable SIR ensures protective immunity. Measles virus may induce asymptomatic SIR in IgG-seropositive subjects. SVF led to typical or modified measles but did not seem to have played an important role during this epidemic.

Measles immunity among community hospital employees

OBJECTIVE

To define measles immunity rates among employees at 2 hospitals during a community outbreak in 1990.

DESIGN

Cohort survey using enzyme-linked immunosorbent assay (ELISA) and questionnaire.

SETTING

Two community hospitals.

PARTICIPANTS

Seventy-six percent of 2,060 employees.

RESULTS

Seven percent (115/1566) of participants lacked ELISA-defined measles immunity. Among employees whose ages were known, 14% (64/467) of those born after 1956 and 5% (50/1086) of those born before 1957 lacked serologic evidence of immunity. Fifty-eight percent of the susceptible persons had substantial patient contact. With ELISA results as the reference for immunity, the predictive value of an undocumented positive history of measles disease or vaccination was 95%; the predictive value of a negative history of both was 52%. Measles developed in 7 employees.

CONCLUSIONS

A substantial number of hospital employees lacked ELISA-defined measles immunity, including many who had patient contact or who had been born before 1957. Undocumented disease and vaccination histories were not adequate predictors of serologic status. This study supports the recommendations and suggestions of the Immunization Practices Advisory Committee that hospitals should require documented evidence of measles immunity from employees who have patient contact.