Level of immune Response of children of the sex and age of 6 months to 10 years to oral (OPV b, nOPV2) and inactivated (IPV) vaccines in the provinces of Maniema and Ituri, In the DRC

The Democratic Republic of the Congo is the country where cases of poliovirus derived from vaccine strains type 1, 2 are circulating. The objective of this study was to assess the level of immune response in children aged 6 months to 10 years old fully vaccinated with OPV and IPVMethods:This is a cross-sectional and evaluative study that was carried out between July 2021 and August 2023 in two provinces of the Eastern DRC and included 348 children. The variables of interest were age, sex, province of origin, and anti-polio serology results.ResultsOut of 348 children, 168 were boys versus 180 girls with a sex ratio of 0.93.Two hundred and four children were from Maniema and 144 were from Ituri. The mean age was 4.7 ± 2.7 years and the median age was 5 years with extremes of 1 to 10 years.The vaccine failure rate was 56.9% for girls and 43.1% for boys. This rate was 59.3% in the Maniema site and 53.5% in the Ituri site. The difference was not statistically significant (p = 0.278). Considering the age groups, the vaccination failure rate was respectively 59.4% in children aged between 5 and 54.5% in those under 5 years of age. There was no statistically significant difference (p = 0.354).Conclusion:This study showed a significant rate of vaccine failure among fully vaccinated children. This result requires further studies to investigate the factors associated with this failure.