Evaluation of Rubella IgG Antibodies Among Women at Marriage in Kermanshah City, Before and After Mass Vaccination

Rubella is a mild viral infectious disease, usually occurs subclinically without a serious complication. But if occurs during pregnancy, specially the first trimester, it can transmit and invade to fetus causing congenital rubella syndrome or fetal death. In 2003, nearly all Iranians at the age of 5 to 25 years old were vaccinated against rubella and the vaccine was included in the compulsory immunization, MMR afterwards. This study was carried out on girls attended at a marriage consultancy center in Kermanshah city (West of Iran) in 2006. Considering 95% of confidence, the sample size was estimated at 140. All samples were tested using ELISA serologic method and compared with similar study conducted on 240 unvaccinated girls at the same place in 1999. Antibody positivity was observed in 99.3%, compared to 79.58% of the previous study. A rise of 19.72% (95% CI 12.7%-26.7%) of seropositivity was observed in vaccinated girls versus unvaccinated ones (P < 0.001). In our previous study, we had recommended to screen for susceptibility to rubella before marriage, which is no longer required since more than 99% of vaccinated girls showed immunity at the time of marriage. However, as sustainability of immunity after rubella vaccination is usually less than immunity due to illness, we recommend screening for rubella protective antibody every few years.