Epidemiological and clinical differences of confirmed and discarded Mpox cases on the 2022 Chilean outbreak

OBJECTIVES: To improve Mpox diagnosis by identifying distinctive symptoms in confirmed vs discarded cases due to outdated case definition. METHODS: This is a case-control study conducted using data from the Institute of Public Health database, encompassing all suspected cases analyzed by real-time polymerase chain reaction between June 1 and September 30, 2022. We calculated means, frequencies, performed Fisher's test, and computed odds ratios (OR) using RStudio and Microsoft Excel. RESULTS: Among 1415 suspected Mpox cases, 87% were men aged 30-39 with exanthema. Confirmed cases had higher rates of lymphadenopathy (31% vs 12%), fever (42% vs 29%), myalgia (35% vs 25%), and specific lesions: pustules (36% vs 27%), scabs (25% vs 17%), and umbilicated lesions (24% vs 7%) (P <0.05). Key risk factors for Mpox included contact with a positive case (OR 2.33), multiple sexual partners (OR 3.52), and male gender (OR 29.93). CONCLUSION: The symptomatology of confirmed Mpox cases closely aligns with that reported in the current outbreak. The primary risk factors identified include prior contact with another positive case, having multiple sexual partners, and male gender. However, to facilitate a more complete analysis, more evidence needs to be investigated.