Prospective screening for monkeypox infection among users of HIV pre-exposure prophylaxis (PrEP) in Denmark

Introduction During the 2022 outbreak of mpox (previously called monkeypox), which primarily affected men who have sex with men (MSM), testing was mainly limited to individuals with symptoms of infection. Although sporadic cases of mpox continue to be diagnosed in Denmark, the benefit of screening asymptomatic high-risk populations, such as those using HIV pre-exposure prophylaxis (PrEP), is still unknown. Methods During the autumn of 2022, a rectal swab test for mpox PCR was included in the routine sexually transmitted infections (STI) screening for PrEP users. Results The screening included 224 asymptomatic men with a median age of 36.5 years. One patient (0.4%) tested positive for mpox. Ten (4.5%) and nine (4.0%) had chlamydia and gonorrhea, respectively. Discussion We found one case of mpox, who developed symptoms three days after testing positive. This finding may reflect low to non-existing levels of asymptomatic infection among mpox patients. Based on the current study, screening for asymptomatic mpox infection among PrEP users does not seem warranted.