Prior Vaccination History Research Articles

Immune response to tissue culture rabies vaccine in subjects who had previous postexposure treatment with Semple or suckling mouse brain vaccine

Nerve tissue derived Semple and suckling mouse brain rabies vaccines are still widely used. Patients who experience a new rabies exposure and who were given such vaccines decades earlier are not uncommon in rabies endemic countries. The World Health Organization recommends that persons who have had a prevous course of a potent tissue or avian culture rabies vaccine and are reexposed, be given booster injections on days 0 and 3 without rabies immune globulin. Persons who have had previous pre- or postexposure vaccination with a vaccine of unproven potency, should receive a full course of tissue or avian cell vaccine and immune globulin in the event of a new exposure. This study evaluated the immune response in 98 Thai patients who gave a history of rabies postexposure treatment with Semple or suckling mouse brain vaccines 10–50 years previously. The majority (81) had an anamnestic response and developed neutralizing antibodies that were above the recommended minimal acceptable level (0.5 IU ml −1) on day 7. This suggests that they still had immunological memory. A minority of 18% had antibody titers below this level on day 7. However, they all developed titers above 0.5 IU ml −1 on days 14 and 30. Failure to have an accelerated response to revaccination by day 7 did not appear to be related to age or time elapsed since previous nerve tissue derived vaccine administration. It was not possible to predict which subject will or will not have an acceptable level of antibody before day 14. Rabies exposed patients who give a prior history of vaccination with an unknown or nerve tissue derived vaccine should therefore be treated as if they had never been vaccinated.

Measles immunity and response to revaccination among secondary school children in Cumbria

The prevalence of antibody to measles virus in 759 children aged 11-18 years attending a secondary school in Cumbria was measured using a salivary IgG antibody capture assay. Serum IgG antibody levels were measured using a plaque reduction neutralization assay in subjects whose saliva was antibody negative. Vaccination histories were obtained from the child health computer and general practice record. A total of 662 pupils (87% of those tested) had detectable measles-specific IgG in saliva. Of the remaining 97, 82 provided blood samples and 29 had serum neutralizing antibody levels above 200 mIU/ml. Afer adjusting for non-participation rates, the proportion considered non-immune (no IgG in saliva and < or = 200 mIU/ml in serum) was 9% overall, ranging from 6% in vaccinated children to 20% in unvaccinated children. Measles-mumps-rubella vaccine was given to 50 children of whom 38 provided post-vaccination serum and 32 saliva samples. Thirty (79%) had a fourfold or greater rise in serum neutralizing antibody and 28 (88%) developed IgG antibody in saliva. Half of the children considered non-immune by antibody testing would have been overlooked in a selective vaccination programme targeted at those without a history of prior vaccination. A programme targeted at all school children should substantially reduce the proportion non-immune since a primary or booster response was achieved in three quarters of previously vaccinated children with low antibody levels and in all unvaccinated children. While it is feasible to screen a school-sized population for immunity to measles relatively quickly using a salivary IgG assay, a simple inexpensive field assay would need to be developed before salivary screening and selective vaccination could substitute for universal vaccination of populations at risk of measles outbreaks. The salivary IgG assay provided a sensitive measure of a booster response to vaccination.

Serological findings during a measles outbreak occurring in a population with high vaccine coverage.

From March 1991 to April 1992, serum samples for IgM detection were collected from 112 clinical measles cases reported to the Health Department of Niterói, State of Rio de Janeiro. The positivity exceeded 90% for specimens collected from the 5th to the 29th day after the onset of the disease. After day 30 a decline in IgM detection was observed, although positivity has been detected up to 90 days after the onset of the symptoms. Forty-four patients (48.9%) with an IgM response had a history of prior measles vaccination. In 5 of the 22 measles-IgM negative cases the infection was due to other agents (rubella: 4 cases, dengue: 1 case). These results show that sensitivity of the test employed for confirming suspected measles cases is high, even in vaccinated patients.

A Single 210-μmol Oral Dose of Retinol Does Not Enhance the Immune Response in Children with Measles

This trial assessed the effect of vitamin A on reversing measles-induced unresponsiveness to recall antigens and on enhancing measles antibody production. These assessments were part of a randomized, double-masked clinical trial of the efficacy of 210 mumol of retinol as retinyl palmitate for reducing measles-associated morbidity. Two hundred children between 5 mo and 17 y of age with acute measles were enrolled at the Urban Health Centers in Ndola, Zambia; 110 subjects received a placebo and 90 received vitamin A. At enrollment and 2 wk later, blood samples were collected to determine measles hemagglutinin antibody titer and, at 1 and 2 wk post-enrollment, cutaneous delayed-type hypersensitivity tests (DTH) for seven antigens were applied. Both groups of subjects showed marked DTH unresponsiveness, but vitamin A-treated subjects had a significant prolongation of unresponsiveness to tuberculin [odds ratio (OR) 3.22 and 95% confidence interval (CI) 1.27-8.2], Candida (OR 5.43, CI 1.13-25.9) and Proteus (OR 5.17, CI 1.14-28.4), after adjustment for previous vaccination and age. DTH unresponsiveness was antigen specific, reflecting prior vaccination history, and was not associated with acute respiratory infection status. In addition, children in both treatment groups showed a significant increase in measles antibody titer from baseline to wk 2, but this increment was not significantly different between the groups (P = 0.25). These results indicate that a single oral dose of 210 mumol of retinol as retinyl palmitate in oil does not enhance the immune system during measles.

Screening of physicians for tuberculosis.

To determine the prevalence of tuberculous infection among a sample of physicians at Barnes Hospital and to determine the frequency of tuberculin skin testing and the adequacy of follow-up for physicians with positive tuberculin skin tests. Convenience sample. 1,000-bed, university-affiliated tertiary care hospital. Physicians attending departmental conferences were screened for tuberculosis. Prior history of tuberculosis, antituberculous therapy, BCG vaccination, and previous tuberculin skin test results were obtained with a standardized questionnaire. Tuberculin skin tests were performed on those who were previously skin-test negative. Tuberculosis infection, prophylactic therapy. Eighty-six (24.5%) of 351 physicians in the study were skin test positive by history or currently performed skin test. Of 61 who reported a previously reactive skin test, 40 (66%) had been eligible for isoniazid prophylaxis, but only 15 (37.5%) of 40 had completed at least six months of therapy. Of 290 physicians reporting a previously negative skin test, 25 conversions (8.6%) were identified. Previously undiagnosed, asymptomatic pulmonary tuberculosis was identified in one physician. Infection with Mycobacterium tuberculosis is common among physicians. Physicians were screened irregularly for tuberculosis, and the use of prophylactic therapy was inconsistent. Aggressive tuberculosis screening programs for healthcare workers should be instituted (Infect Control Hosp Epidemiol 1994;15:95-100).

Immunoglobulin M antibody response to measles virus following primary and secondary vaccination and natural virus infection

The use of IgM antibody detection for the classification of the primary and secondary measles antibody response in persons following primary and secondary vaccination and natural measles virus infection was examined. Of 32 nonimmune children receiving primary measles vaccination, 31 (97%) developed IgM antibodies, consistent with a primary antibody response. Of 21 previously vaccinated children with low levels of preexisting IgG antibodies who responded to revaccination, none developed detectable IgM antibodies, whereas 33 of 35 (94%) with no detectable preexisting IgG antibodies developed an IgM response. Of a sample of 57 measles cases with a prior history of vaccination, 55 (96%) had detectable IgM antibodies. Of these, 30 (55%) were classified as having a primary antibody response and 25 (45%) a secondary antibody response based on differences in their ratios of IgM to IgG antibodies. Differences in the severity of clinical symptoms between these 2 groups were consistent with this classification scheme. These findings suggest that 1) an IgM response follows primary measles vaccination in the immunologically naive, 2) an IgM response is absent on revaccination of those previously immunized, and 3) an IgM response may follow clinical measles virus infection independent of prior immunization status.

Pneumococcal Vaccination: When in Doubt, Go Ahead

To the Editor.— Although universal immunization against pneumococcal disease is desirable, the calls for blanket immunization presented in the September 5 issue 1 do not adequately address two concerns. Notwithstanding unfounded concerns about adverse reaction, the 1990 Physicians' Desk Reference continues to state, Re-vaccination of adults is contraindicated... since an increased incidence and severity of adverse reactions among healthy adults receiving such re-injections have been noted. When faced with uncertainty as to whether a patient has had previous vaccination, and with such a dire warning, it is not surprising that many physicians will demur. It is unreasonable to expect the medical community to ignore this risk in today's litigious society. Because many patients are unable to give a reliable history of prior vaccination, more thought should be given to a foolproof system of documenting immunization. Use of a harmless dye in the vaccine, together with a convention that immunization always

High Rate of Tuberculin Conversion in Indochinese Refugees

From January 1979 through December 1980, a total of 664 Indochinese refugees were screened for tuberculosis in Monroe County, New York; 307 (46%) had positive 5-tuberculin unit PPD Mantoux tests. When 217 refugees with initially negative tests were retested at 60 days, 94 (43%) had converted from a negative to a positive test. Although none of the converters had evidence of active tuberculosis disease, 90 (96%) were given isoniazid preventive therapy. This conversion phenomenon has continued over time, discounting an effect of local, national, or international policy changes. The conversions do not seem to be a function of antigen, tester, or reader; criteria for testing, retesting, or reading; home country, camp country, or length of time in camp; or history of prior BCG vaccination, tuberculosis, or immunization exposure, current illness, or testing intervals since arrival in the United States and subsequent testing. Further studies to evaluate boosting or anergy are in progress to assess this potential public health problem.