This study is investigating a medicine called tecovirimat to help treat the human mpox virus (HMPXV), a virus that can cause skin and mouth sores. The study involves two groups: one group gets the medicine, and the other gets a placebo, a fake pill that doesn’t have real medicine. If you have severe symptoms, are under 18, or are pregnant, you will get the real medicine. The study lasts 57 days.

Key Points:

• Participation Length: 57 days with medication for 14 days.
• Visits: Weekly check-ups until day 29, and one final visit on day 57.
• Eligibility: Must have mpox symptoms for less than 14 days and at least one active sore.

During the study, you will monitor your sores daily and report any symptoms. If your condition worsens, you will switch to the real medicine. You can join if you’ve had mpox symptoms for less than 14 days and have at least one active sore. You cannot join if you’ve already taken tecovirimat or need it through an IV. It's important to know that non-pregnant participants must use birth control during the study.