Modelling to inform the COVID-19 response in Bangladesh

Abstract

AbstractBackgroundNon-pharmaceutical interventions (NPIs) used to limit SARS-CoV-2 transmission vary in their feasibility, appropriateness and effectiveness in different contexts. In Bangladesh a national lockdown implemented in March 2020 exacerbated poverty and was untenable long-term, and a resurgence in 2021 warranted renewed NPIs.MethodsWe developed an SEIR model for Dhaka District, parameterised from literature values and calibrated to data from Bangladesh. We discussed scenarios and parameterisations with policymakers with the aid of an interactive app. These discussions guided modelling of lockdown and two post-lockdown measures considered feasible to deliver; symptoms-based household quarantining and compulsory mask-wearing. We examined how testing capacity affects case detection, and compared NPI scenarios on deaths, hospitalisations relative to capacity, working days lost, and cost-effectiveness.ResultsLockdowns alone were predicted to delay the first epidemic peak but could not prevent overwhelming of the health service and were costly in lost working days. Impacts of post-lockdown interventions depended heavily on compliance. Assuming 80% compliance, symptoms-based household quarantining alone could not prevent hospitalisations exceeding capacity, whilst mask-wearing prevented overwhelming health services and was cost-effective given masks of high filtration efficiency. Combining masks with quarantine increased their impact. Even at maximum testing capacity, confirmed cases far underestimate total cases. Recalibration to surging cases in 2021 suggests potential for another wave later in 2021, dependent on uncertainties in case reporting and immunity.ConclusionsMasks and symptoms-based household quarantining synergistically prevent transmission, and are cost-effective in Bangladesh. Our interactive app was valuable in supporting decision-making, with mask-wearing being mandated early, and community teams being deployed to support quarantining across Dhaka. These measures likely contributed to averting the worst public health impacts, but delivering an effective response at scale has been challenging. Messaging to increase compliance with mask-wearing and quarantine is needed to reduce the risk and impacts from another wave.