Investigation of Fatal Chickenpox Outbreak among Adults in Northern Bangladesh, 2023

• Adult predominance observed in a rural chickenpox outbreak in Bangladesh • Fatal adult cases linked to delayed care-seeking and comorbidities • Thrombocytopenia and pneumonia identified in both fatal cases • Strong reliance on traditional healers delayed formal healthcare access Although chickenpox is usually mild and self-limiting, severe complications and death may occur among adults. In April 2023, two adult deaths associated with clinically diagnosed chickenpox in a remote village of northern Bangladesh triggered notification of a suspected outbreak and prompted an investigation to describe its epidemiological characteristics and contextual factors associated with severe adult cases. A mixed-method outbreak investigation was conducted from 15–19 April 2023 in Thakurgaon district. Active case finding, household visits, line listing, and verbal autopsies were performed. Vesicular swabs were tested for varicella-zoster virus (VZV) by polymerase chain reaction (PCR). Environmental assessments and a focus group discussion explored contextual factors, community perceptions, and care-seeking behavior. Twenty-three confirmed cases were identified, including seven laboratory-confirmed cases. The attack rate was 1.2% and the case fatality rate 8.7%. Adults over the age of 20 comprised 52.2% of cases and males 60.9%. Both fatal cases were adult males with comorbidities, heavy smoking history, delayed care-seeking, pneumonia, and thrombocytopenia. All samples were PCR-positive for VZV. The epidemic curve suggested propagated transmission. Qualitative findings indicated reliance on traditional healers and delayed formal care. Chickenpox can result in severe and fatal outcomes among adults in resource-limited settings. Early recognition and timely healthcare access are critical to reducing mortality.