Photo Credit: Marina Demidiuk
The following is a summary of “A seroprevalence study indicates a high proportion of clinically undiagnosed MPXV infections in men who have sex with men in Berlin, Germany,” published in the October 2024 issue of Infectious Diseases by Marcus et al.
Researchers conducted a retrospective study to estimate the frequency of clinically undiagnosed mpox infections among men who have sex with men (MSM) in Berlin during the 2022 outbreak.
They examined the participants recruited from private practices and community-based checkpoints specializing in HIV and STI care for MSM and were asked to complete an online questionnaire on socio-demographic data, mpox diagnosis, vaccination history, and sexual behavior, and to provide a blood sample for serological analysis. The samples were tested for antibodies against various antigens to distinguish between antibodies induced by mpox infection and MVA vaccination, with pre-immune sera from childhood smallpox vaccination as a confounding factor. The associations of behavioral variables with reported and suspected mpox diagnosis were tested using univariable and multivariable logistic regression models.
The results showed that 1,119 participants were recruited from April 11 to July 1, 2023, across 8 private practices and 2 community-based checkpoints in Berlin. Each participant provided a blood sample for serological testing. An online questionnaire was completed by 728 participants, while core data on age and mpox history were gathered from an additional 218 participants who did not fill out the questionnaire. Among the participants, 70 (7.4%) reported a previous diagnosis of mpox. Using conservative and strict case definitions, 91 individuals were serologically identified as having suspected undiagnosed mpox infection. Individuals with reported or suspected mpox infections had an elevated number of condomless anal sex partners in the past 3 months, with an odds ratio (OR) of 5.93 (95% confidence interval [CI] 2.10-18.35) for 5–10 partners and an OR of 9.53 (95% CI 2.72–37.54) for more than 10 partners. Additionally, these individuals were more likely to report sexual contact with partners diagnosed with mpox, with an OR of 2.87 (95% CI 1.39–5.84).
They concluded that a significant percentage of mpox infections were clinically undiagnosed, and the number of condomless anal sex partners was strongly linked to both confirmed and suspected undiagnosed mpox infections.
Source: bmcinfectdis.biomedcentral.com/articles/10.1186/s12879-024-10066-z
