Rotavirus and adenovirus infections in children with acute gastroenteritis after introducing the Rotasiil® vaccine in Kisangani, Democratic Republic of the Congo

Background Although rotavirus vaccination has reduced the global burden of the virus, morbidity and mortality from rotavirus infection remain high in Sub-Saharan Africa. This study aimed to determine the prevalence of rotavirus and adenovirus infections in children under five years with acute gastroenteritis and to identify factors associated with rotavirus infection after the introduction of the Rotasiil ® vaccine in 2019 in Kisangani, Democratic Republic of the Congo (DRC). Methods This study consisted of a cross-sectional hospital-based survey conducted from May 2022 to April 2023 in four health facilities in Kisangani, using a fecal-based test (rapid antigenic immuno-chromatographic diagnostic test, BYOSYNEX adenovirus/rotavirus BSS, Biosynex SA, Illkirch-Graffenstaden, France) of rotavirus and adenovirus infections among children under five years of age with acute gastroenteritis. Results A total of 320 children under five years of age with acute gastroenteritis were included. The prevalence of rotavirus infection was 34.4%, that of adenovirus was 6.3%, and that of both rotavirus and adenovirus coinfection was 1.3%. The prevalence of rotavirus was significantly higher in unvaccinated children than in vaccinated children (55.4% versus 23.1%; P < 0.001). This difference was observed only in children who received all three vaccine doses. Multivariate logistic regression analysis shows that the rate of rotavirus infection was significantly reduced in vaccinated children (adjusted OR: 0.31 95% confidence intervals (CI): 0.19–0.56; P < 0.001) and those whose mothers had an average (adjusted OR: 0.51 95% CI: 0.25–0.91; P = 0.018) or high level (adjusted OR: 0.34 95% CI: 0.20–0.64; P < 0.001) of knowledge about the rotavirus vaccine. Conclusions The prevalence of rotavirus infection remains high in Kisangani despite vaccination. However, the prevalence of adenovirus infections was low in our series. Complete vaccination with three doses and mothers’ average and high level of knowledge about the rotavirus vaccine significantly reduces the rate of rotavirus infection. It is, therefore, essential to strengthen the mothers’ health education, continue with the Rotasiil ® vaccine, and ensure epidemiological surveillance of rotavirus infection.