Tecovirimat resistance in an immunocompromised patient with mpox and prolonged viral shedding

Helena Mertes, Antonio Mauro Rezende, Isabel Brosius, Reinout Naesens, Johan Michiels, Tessa de Block, Jasmine Coppens, Christophe Van Dijck, Peter Bomans, Emmanuel Bottieau, Marjan Van Esbroeck, Kevin K Ariën, Laurens Liesenborghs, Koen Vercauteren

Research output: Contribution to journalLetterpeer-review


Background: Tecovirimat, an inhibitor of the viral VP37 envelope-wrapping protein used to treat severe monkeypox virus (MPXV) infection, has a low barrier to resistance (1, 2). A tecovirimat-resistant MPXV variant was recently identified at the autopsy of an immunocompromised patient with mpox after prolonged tecovirimat treatment (3).

Objective: To describe the rapid selection of a tecovirimat-resistant MPXV variant during treatment of a severely immunocompromised patient with prolonged MPXV infection.

Case Report: A 53-year-old man who had been vaccinated for smallpox in childhood presented in November 2022 with weight loss; a longstanding large, painful anal ulcer; and proctitis, but without skin lesions. Work-up revealed HIV-1 infection with pronounced immunosuppression (plasma viral load, 523 000 copies/mL; CD4+ T-lymphocyte count, 0.02 × 109 cells/L), chronic hepatitis B virus infection, latent syphilis, Cryptococcus neoformans antigenemia, anal Chlamydia trachomatis infection, and cytomegalovirus infection.
Original languageEnglish
JournalAnnals of Internal Medicine
Issue number8
Pages (from-to)1141-1143
Number of pages3
Publication statusPublished - 2023

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