Rotavirus infection among children under five years of age hospitalized with acute gastroenteritis in Myanmar during 2018–2020 – Multicentre surveillance before rotavirus vaccine introduction

•This study describes rotavirus epidemiology before rotavirus vaccine introduction in Myanmar.•Rotavirus detection was 45.7% in May 2018–Apr 2019 and 42.5% in May 2019–Jan 2020.•The highest proportion of positivity was among 6–11 month old children (41.6%).•Diversity of rotavirus strains over time before vaccine introduction was found.•This study will be important baseline data for monitoring of vaccine impact. Rotavirus gastroenteritis (RVGE) is a leading cause of severe diarrhea in children under-five worldwide, with the majority of mortality in lower -income countries. This study aimed to provide baseline information on epidemiology of rotavirus and circulating strains before rotavirus vaccine introduction in Myanmar. Hospital-based, prospective surveillance was conducted from May 2018 to January 2020 at four sentinel sites; two hospitals in Lower Myanmar, one hospital each in Middle Myanmar and East Myanmar. Children under five years of age hospitalized for acute gastroenteritis were enrolled; demographic and clinical data were collected. Stool samples were screened by ELISA (ProSpecT™ Rotavirus, OXOID-UK) for rotavirus antigen and a subset of ELISA positive samples were genotyped by reverse transcription polymerase chain reaction. Rotavirus was detected in 45.7% (799/1750) of cases enrolled at three sites in May 2018–April 2019 and 42.5% (521/1227) at four sites in May 2019–January 2020. RVGE cases were predominantly male (58.7%; 775/1320) and 92.6% (1223/1320) of RVGE cases occurred in