Title : Sentinel surveillance of acute rotavirus gastroenteritis in under-five children in selected hospitals across 4 geopolitical zones of Nigeria 2020-2023
Abstract:
Introduction: Nigeria shares disproportionate global cases of rotavirus gastroenteritis of children under five years of age which stood at 14% and accounts for the second-highest mortality rate in this age group. The nation is implementing a nationwide vaccination program against rotavirus to reduce the incidence and severity of the disease. However, active case search through robust, continuous and effective national surveillance systems is needed to track the disease trends, evaluate vaccine impact, and identify both circulating and emerging RVA variants. A sentinel surveillance system was implemented in 2019 to achieve this purpose. We report the results of surveillance for this disease for the first 37 months of operation.
Methods: The study was conducted from November 2020 to January 2023 in selected hospitals across four geopolitical zones of Nigeria, namely ADH (Northcentral), AKTH (Northwest), NAUTH (Southeast), and LASUTH (Southwest). A cumulative 215 children under five years of age who met the case definition for acute rotavirus diarrhoea were enrolled. Case demographic and epidemiologic data with corresponding stool samples were collected. Stool samples were tested using anti-rotavirus IgM ELISA at the NCDC National Reference Laboratory. Both results were analyzed, integrated, and interpreted for informed policy decisions and actions.
Results: The overall seroprevalence of 46.9% (101/215) IgM was observed. Male and female had 51.3% (58/113) and 42.1% (43/102) seropositivity rates respectively. The sites’ IgM seropositivity distribution rates are: ADH 44% (55/125), AKTH 57.7% (26/45), LASUTH 29.6% (8/27), and NAUTH 66.6% (12/18). Age-related IgM seropositivity shows an ascending rate from ages 0-6 months (37.5%), 7-12 months (45.4%), 13-24 months (50%) to 25-60 months (60%). Infection trends showed activity throughout the period of study with peak activities observed in December 2020; March and August of 2021; January, July and November of 2022. Only 1.8% (4/215) of the children were vaccinated and 0.4% (1/215) tested positive.
Conclusion: Each sentinel site presented with differing seroprevalences, which may indicate regional differences or unequal subject matching. All-around activity with peak infection rates during rainy and dry seasons was manifested. The number of vaccinated children was low. More intensive surveillance will be needed to unfold the extent of the disease in the selected sentinel sites.
