Seroprevalence of Measles-Specific IgM and IgG Antibodies Among Children Aged 0-12 Years in Northeast Nigeria

Background The WHO AFRO region, including Nigeria, targeted 2020 for measles elimination, requiring the achievement of five key indicators. Nigeria's strategy includes improving MCV1 coverage at 9 months, supplemental immunization for children aged 9–59 months, and intensified case-based surveillance. Recently, MCV2 was introduced and is being piloted. Achieving at least 95% coverage with MCV2 at 15 months is essential for herd immunity. Despite efforts, measles outbreaks persist, worsened by armed conflicts and the COVID-19 pandemic in northeast Nigeria. This study aimed to describe measles seroprevalence in parts of northeast Nigeria and evaluate the correlation between measles cases and socio-demographic and risk factors using serological data. Methods A seroprevalence study was conducted in three states of northeast Nigeria among children aged 0–12 years. The study analyzed 558 serum samples for measles-specific IgM antibodies and 372 serum samples for measles-specific IgG antibodies. IgM antibodies were determined using the EUROIMMUN measles virus IgM ELISA kit, and IgG antibodies were determined using the Calbiotech measles IgG kit. The relationship between measles and socio-demographic and risk factors was analyzed using chi-square tests at P  < 0.05. Results Out of 558 children, 163 (29.2%) tested positive for measles IgM antibodies, and out of 372 children, 122 (32.7%) tested positive for measles IgG antibodies. Male children (30.6%) were more affected than female children (28.1%), although the difference was not statistically significant (p = 0.521). The highest infection rate (40.8%) was among children aged 1–3 years. A significant number (295; 40.3%) of infected children were unvaccinated. Higher infection rates were observed among children whose parents had primary education (34.3%) and those from very low socio-economic status (33.8%). There was a statistically significant correlation (p = 0.000) between poor nutritional status (46.7%) and infection rate. Conclusion These data confirm the presence of the measles virus among children and highlight the burden of the disease in northeast Nigeria. A second vaccine dose must be considered a national priority to address the failures of the first dose and to adhere to WHO recommendations for measles control and elimination.