Rubella Antibody Avidity Among Rubella Seropositive Women Attending a Tertiary Care Facility in Nigeria

The aim of this study was to determine the seroprevalence of rubella virus antibodies among women of reproductive age group and assess risk factors of rubella infection. A cross-sectional study was carried out among 285 women aged between 15 and 49 years. Enzyme-linked immunosorbent assay (ELISA) method was used to detect and quantify human immunoglobulin G (IgG) antibodies with avidity for rubella virus in sera of participants. Socio-demographic characteristics of the participants, along with recent and previous history of fever and rash among others were obtained using a questionnaire. Statistical analysis was carried out using SPSS version 16. Seroprevalence of rubella IgG among women of reproductive age in Ilorin was 92.3% (95% CI: 89.2%-95.4%). Thus susceptibility rate to rubella infection was 7.7%. Majority (87.1%) of the IgG seropositive participants had high rubella IgG avidity, implying past rubella infection or reinfections. Seroprevalence was significantly higher among participants from lower educational and socio-economic classes compared with other participants (P =. 035 and P =. 023, respectively). There was a negative correlation between age and rubella specific IgG titer (P =. 000). Thus rubella specific IgG titer decreases with increasing age. There is need for vaccination of susceptible women of reproductive age in Ilorin as the rubella susceptibility rate was higher than the 5.0% target set by the World Health Organization (WHO) for prevention of congenital rubella syndrome (CRS).