Measles IgG sero-prevalence and its attributable factors in 5–25-year-old cases prior mass vaccination campaign in Urmia, northeastern Iran
نویسندگان
1 Department of Community Medicine
2 Department of Community Medicine
3 Department of Health Education
4 Department of Immunology, Faculty of Medicine, Urmia University of Medical Sciences, Urmia, Iran.
5 Department of Immunology, Faculty of Medicine, Urmia University of Medical Sciences, Urmia, Iran.
doi
چکیده
Measles is a vaccine preventable infectious disease. Despite the widespreadavailability of an effective measles vaccine, the number of measles cases is noticeable inIran. Because measles –specific antibody titer after vaccination is lower than after naturalinfection there is a concern that vaccinated persons may gradually lose protection frommeasles. This study was performed to examine the persistence of vaccine-induced antibody,participants with documented history of vaccination were assessed to determine thesero-prevalence and titer of measles antibody.Methods: This study was carried out in Urmia. Iran. Documented history of at least a singledose of live attenuated measles vaccine (at 9 or 15 month of age) was the inclusion criteria.Blood was collected from 835 subjects between 5 and 25 years old. The sera weretested for anti-measles IgG antibodies, by ELISA (IBL Germany). Associations betweenpredictive factors such as demographic data, vaccination status (once or twice) with IgGsero prevalence in routine vaccinated subjects were investigated by logistic regressionanalysis.Results: The antibody titers in 54.76% of cases were in the range of protective level(IgG>12IU). The mean of antibody titer significantly increased after the 16th year of life.The antibody titers were higher in participants who received one dose of measles vaccine incomparison with the persons who received a booster of measles vaccine. Antibody titerswere slightly higher in men than in women. On multiple logistic regression analysis, of allvariables examined, only vaccination status retained a significant association with antimeaslessero-positivity rate (estimated odds ratio = 0.395 95%CI = 0.214-0.859, P<0.05).Conclusion: Elevation of antibody titer many years after vaccination is most likely due toboosting effect from repeated exposure to circulating wild virus resulting in unapparent orsub-clinical re-infection. This group of persons would be the most likely to support viraltransmission in the absence of disease.
