Transmission Dynamics of Mpox in Peru During the 2022 Outbreak

In July 2022, mpox was declared an international public health emergency because of a surge in cases across Europe and America. This study assessed transmission dynamics and factors associated with hospitalization during the 2022 mpox outbreak in Peru. We performed a cross-sectional study using the Surveillance System of the National Center of Epidemiology, Prevention, and Disease Control (CDC-Peru) data. We estimated the basic reproduction number (R0), effective reproduction number (Rt), and the duration of the outbreak phases. We conducted mathematical modeling of the outbreak and estimated the serial interval. Additionally, we used Poisson regression with robust variance to identify hospitalization factors, using prevalence ratio. Between July and December 2022, 3,677 confirmed cases (96.3% male, mean age 32.6 years) were reported to the CDC-Peru. Of these, 75.0% were men who have sex with men (MSM), 55.6% had HIV infection, and 5.2% were hospitalized. The R0 was 2.37, with an exponential growth phase lasting 7 weeks, and Rt dropped to non-epidemic levels after 14 weeks. The incubation period and recovery period were estimated to be 6 days and 22 days, respectively. The serial interval was 9.3 days. HIV infection increased hospitalization risk. The 2022 mpox outbreak in Peru was characterized by primarily affecting a young MSM population, with a significant proportion being people living with HIV. Hospitalization was associated with HIV coinfection. This outbreak showed exponential growth during the first 7 weeks, followed by a marked deceleration of transmission.