Seroprevalence of Measles Virus Antibodies in Children Post-Vaccination in Jigawa State

Measles remains a leading vaccine-preventable cause of child mortality in Nigeria, with resurgent outbreaks in the North West and North East geopolitical zones indicating gaps in vaccine-induced immunity. This study determines the seroprevalence of measles virus IgG antibodies in children aged 9 months to 5 years who received measles-containing vaccine through routine immunisation in Jigawa State. A cross-sectional serosurvey will enrol 360 children through cluster sampling from 20 wards across four local government areas. Serum samples will be tested for measles IgG using a quantitative ELISA, and results will be classified as seropositive (protected) or seronegative (susceptible). Vaccination cards will be reviewed to confirm vaccine receipt and dose number. Factors assessed for association with seronegativity will include age at vaccination, cold chain exposure, maternal education, and nutritional status. Published vaccine efficacy data suggest that up to 15 percent of recipients fail to seroconvert after a single measles dose, with higher failure rates associated with poor cold chain maintenance in remote districts. Findings will provide evidence on the proportion of apparently vaccinated children who lack protective immunity, supporting a targeted supplemental immunisation campaign in Jigawa State. This study contributes to the national measles elimination goal and informs the National Primary Health Care Development Agency's immunisation quality assurance procedures in North West Nigeria. Keywords: measles, seroprevalence, vaccine-induced immunity, children, Jigawa State