This is the first report of COVID‐19 in a human T‐cell lymphotropic virus type‐1 (HTLV‐1) carrier. HTLV‐1 infection can cause immune dysfunction even in asymptomatic carriers. This case highlights the need for guidance on management of COVID‐19‐HTLV‐1 coinfection, specifically on the appropriate use of corticosteroid treatment while considering secondary infection. [ABSTRACT FROM AUTHOR]