Incidence of Hospitalization due to Influenza‐Associated Severe Acute Respiratory Infection During 2010–2019 in Bangladesh

Abstract

ABSTRACTBackgroundGlobal influenza‐associated acute respiratory infections contribute to 3–5 million severe illnesses requiring hospitalization annually, with 90% of hospitalizations occurring among children < 5 years in developing countries. In Bangladesh, the inadequate availability of nationally representative, robust estimates of influenza‐associated hospitalizations limits allocation of resources for prevention and control measures.MethodsThis study used data from the hospital‐based influenza surveillance (HBIS) system in Bangladesh from 2010 to 2019 and healthcare utilization surveys to determine hospital utilization patterns in the catchment area. We estimated annual influenza‐associated hospitalization numbers and rates for all age groups in Bangladesh using WHO methods, adjusted for a 6‐day‐a‐week enrollment schedule, selective testing of specimens from children under five, and healthcare‐seeking behavior, based on the proportion of symptomatic community participants seeking healthcare within the past week. We then estimated national hospitalization rates by multiplying age‐specific hospitalization rates with the corresponding annual national census population.ResultsAnnual influenza‐associated hospitalization rates per 100,000 population for all ages ranged from 31 (95% CI: 27–36) in 2011 to 139 (95% CI: 130–149) in 2019. Children < 5 years old had the highest rates of influenza‐associated hospitalization, ranging from 114 (95% CI: 90–138) in 2011 to 529 (95% CI: 481–578) in 2019, followed by adults aged ≥ 65 years with rates ranging from 46 (95% CI: 34–57) in 2012 to 252 (95% CI: 213–292) in 2019. The national hospitalization estimates for all ages during 2010–2019 ranged from 47,891 to 236,380 per year.ConclusionsThe impact of influenza‐associated hospitalizations in Bangladesh may be considerable, particularly for young children and older adults. Targeted interventions, such as influenza vaccination for these age groups, should be prioritized and evaluated.