Clinical and epidemiological characteristics of the 2022-2023 Mpox outbreak in Buenos Aires, Argentina.

Introduction: The 2022-2023 Mpox outbreak in Argentina presented unique challenges due to the lack of vaccination and antiviral therapy. This study analyzed the epidemiological and clinical characteristics of cases in the Buenos Aires Metropolitan Area (MABA), examining temporal trends, HIV status, and concomitant sexually transmitted infections (STIs).

Materials and methods: An ambispective, analitic, and multicenter study was conducted between September 2022 and May 2023 in HIV/STI clinics and hospitals in MABA. Cases were classified as confirmed (positive PCR) or possible (clinical and epidemiological criteria). Patients infected with MPox with and without HIV were compared.

Results: 247 patients were included, 95.5% were confirmed cases. The median age was 36 years; 98% were men; 93.7% were men who have sex with men. Sexual exposure was the main transmission route (91%). The 25.2% presented concomitant STIs. The 74% were people living with HIV (PLWH), with good immuno-virological control. Common clinical manifestations included papular, pustular, and vesicular lesions; 59.4% presented >20 lesions. Rectal involvement occurred in 25.6%. Complications were observed in 9.3%, hospitalization in 6.6%, and mortality was 0.4%. PLWH showed a higher prevalence of perianal lesions and proctitis, without differences in complications and hospitalization.

Discussion: The outbreak in Argentina, mainly affecting men who have sex with men living with HIV, had low mortality. No significant differences were observed in complications and hospitalization between people with and without HIV.