Abstract Body


The European mpox exponential increase during the early summer 2022 was believed to be linked to major LGBTQI+ sex-related events. However, it inexplicably faded in the last months of the year: main proposed reasons included behavioural changes in sexual habits and immunization through vaccination campaigns started during summer. We compared the trends of mpox and classical STIs in MSM PLWH and PrEP-users in relation to sex-related events and vaccination campaigns in highly-involved European countries over 2022.


We enrolled consecutive self-identified MSM attending two large sexual health clinics in Milan, Italy, from January to December 2022, who underwent an STIs screening and mpox evaluation. We focused on PLWH and PrEP-users for their strict link to healthcare and regular STIs screening. N. gonorrhoeae, C. trachomatis, M. genitalium and mpox were detected through Nucleic Acids Amplification Tests while a serologic Rapid Plasma Reagin test was used to identify new syphilis cases. Also, we noted the timing for major European LGBTQI+ sex-related events and for the beginning of the mpox vaccination campaign.


1281 STIs were diagnosed from January to December 2022, of whom 654 in PLWH, 627 in PrEP-users. STIs peaked as follows: Chlamydia infection in October (49 cases), followed by January and July (42 and 45 cases), gonorrhoea in June (38), November (37) and January (36), syphilis in August (35 cases), February and March (34 each); mpox in June and July (49 cases) [Figure 1].


We found that classical STIs had a fluctuating, still constant presence throughout the year, while mpox showed a decline even if, in the same period, the mentioned events continued to be held. These findings suggest the unlikeliness of a behavioural change in influencing such a decline, putting in a new light the role of vaccination in the MSM community.