SARS-CoV-2 Seroprevalence before Delta Variant Surge, Chattogram, Bangladesh, March–June 2021
Taufiqur Rahman Bhuiyan, Juan Dent Hulse, Sonia T. Hegde, Marjahan Akhtar, Taufiqul Islam, Zahid Hasan Khan, Ishtiakul Islam Khan, Shakeel Ahmed, Mamunur Rashid, Rumana Rashid, Emily S. Gurley, Tahmina Shirin, Ashraful Islam Khan, Andrew S. Azman, Firdausi Qadri
Abstract
T hrough November 9, 2021, Bangladesh had re- ported >1.57 million COVID-19 cases and 27,904 deaths (1), with incidence and mortality rates substantially lower than in many other countries. Without performing population-based seroprevalence estimates, it is diffi cult to know whether differences in rates of illness and death result from undercounts because of limited surveillance and healthcare seeking or refl ect actual differences in incidence resulting from interventions or different biological responses to infection. In early March 2021, cases across Bangladesh began to rise at the same time as the Delta variant was detected in neighboring India. Publicly available sequencing data (2) indicate that the SARS-CoV-2 Delta variant was fi rst detected in the Chattogram region of Bangladesh in mid-May 2021, and 99% (98/99) of the viral genomes submitted during July 1-October 1, 2021 have been of the Delta variant, similar to national trends.