The study is a phase 3, randomized, placebo-controlled, double-blind trial of tecovirimat for the treatment of
human monkeypox virus (HMPXV) disease. The study will also include a cohort of people who will receive open-label tecovirimat including people with protocol-defined severe HMPXV, pregnant and breastfeeding individuals, individuals less than 18 years of age, individuals on potent inducing concomitant medications, people with severe immune suppression or skin conditions placing them at higher risk for severe disease.