We report 2 immunocompetent and otherwise healthy adults in the United States who had monkeypox and required hospitalization for viral myocarditis. Both patients were unvaccinated against orthopoxviruses. They had shortness of breath or chest pain and elevated cardiac biomarkers. No immediate complications were observed. They were discharged home after symptoms resolved.
Keywords: United States; immunocompetent; monkeypox; myocarditis; orthopox; sexually transmitted infections; unvaccinated; vaccine-preventable diseases; viruses.