Abstract:
Introduction: Rotavirus infection is a leading cause of severe diarrhea culminating to dehydration among children under five years of age. Understanding trends and factors that could assist towards devising effective preventive strategies of Rotavirus infection beyond vaccination is crucial. Objectives: This study was done in an attempt to determine the prevalence and associated factors of Rotavirus infection among vaccinated children aged between 6 weeks and 24 months admitted with acute diarrhea Mwanza, Tanzania. Material and

Methods: Across sectional study involving vaccinated children aged 6 weeks to 24 months was conducted in three selected hospitals from July 2017 to January 2018. Socio-demographic and other relevant clinical information were collected using a standardized data collection tool adopted from WHO Rotavirus surveillance tool. Rotavirus infection from the stool was detected using an enzyme immunoassay. Data were analyzed using STATA version 13.

Results: A total of 301 vaccinated children with acute diarrhea with a median age of 12 [IQR: 8 - 17] months were enrolled. Nine (3.0%) and 292 (97.0%) had received one dose and two doses of Rotavirus vaccine, respectively. The prevalence of Rotavirus infection was 74 (24.6%) [95% CI: 20.0 - 29.8]. Independent predictors of Rotavirus infection were: dry season (OR 6.9; 95% CI: 2.9 - 16.0; p < 0.001), 3 ≥ children indwelling in the same house (OR 2.1; 95% CI: 1.1 - 4.2; p = 0.043) and vomiting (OR 3.6; 95% CI 1.1 - 12.6; p = 0.045). Children with Rotavirus infection had a significantly shorter hospital stay than those without Rotavirus infection (3 [2 - 4] days versus 3 [3 - 5] days; p = 0.0297).

Conclusions: The prevalence of Rotavirus infection has declined among vaccinated children in Mwanza, Tanzania with significant decrease in the hospital stay. Dry seasons, three or more children indwelling in the same house and vomiting were independent predictors of Rotavirus infection. There is a need to sustain the coverage of rotavirus vaccination in low-income countries in order to significantly reduce associated morbidity and mortality.