Challenges in Managing Treatment-Resistant Mpox Complicated by Severe Superinfection

Abstract

Though typically self-limiting, severe mpox infections have been treated with antiviral medications, most notably tecovirimat. Various reports of mpox progression despite tecovirimat treatment exist. Treatment-resistance can be due to acquired mpox strain mutations, most often occurring in an immunocompromised host. We present the case of a male with acquired immunodeficiency syndrome (AIDS) who developed disseminated, treatment-resistant mpox infection complicated by superimposed bacterial and fungal infections. His orthopoxvirus PCR remained positive despite treatment with four weeks of oral tecovirimat and three doses of intravenous cidofovir. Poor response to antiviral therapy was likely due to his underlying immunocompromised state; however, strain resistance cannot be ruled out given that the patient had started, but not completed, a 14-day course of tecovirimat eight months prior at the time of initial mpox diagnosis. Immunocompromised patients with mpox may require extended and additional treatment beyond the standard 14 days of tecovirimat, such as cidofovir, brincidofovir or intravenous vaccina immune globulin.