RT Journal Article SR Electronic T1 O05.4 Changes in MSM’s sexual activity, PrEP use, and access to HIV/STI testing during and after the first Dutch COVID-19 lockdown JF Sexually Transmitted Infections JO Sex Transm Infect FD BMJ Publishing Group Ltd SP A26 OP A26 DO 10.1136/sextrans-2021-sti.77 VO 97 IS Suppl 1 A1 P Adam A1 E Op de Coul A1 W Zuilhof A1 P Zantkuijl A1 C Den Daas A1 J De Wit YR 2021 UL http://sti.bmj.com/content/97/Suppl_1/A26.2.abstract AB Background The COVID-19 pandemic and associated lockdowns have impacted MSM’s sexual activity and access to HIV/STI-related services. This study among MSM in the Netherlands assesses COVID-19-induced changes in numbers of sex partners, condomless anal intercourse (CAI), PrEP use, and HIV/STI testing.Methods From July 20th to September 11th 2020, MSM were recruited via social media to complete an online survey. 2182 respondents (Mage=40 years) provided data on their sexual activity in 3 bimesters before the first lockdown (T1 Jan.–Feb.), during the lockdown (T2 mid-March-mid-May) and after the lockdown (T3 June–July). PrEP use and HIV/STI testing were reported per semester.Results The mean number of sex partners decreased by 39% between T1 and T2 and remained 12% lower at T3 than at T1. The number of CAI partners decreased by 36% between T1 and T2, and at T3 was similar to T1. A majority (62%) of PrEP users stopped using PrEP at some point because of COVID-19, of which 73% subsequently resumed PrEP. A fifth (20%) of respondents postponed/missed appointments for STI testing and 16% postponed/missed appointments for HIV testing. Only 39% of these respondents caught up on missed testing. Self-sampling/testing accounted for 1% of HIV testing and 1.2% of STI testing in the last semester before COVID-19 (past 7–12 months), and 5.5% and 2.7% respectively in the first semester with COVID-19 (past 0–6 months).Conclusion Sexual behaviours that put MSM at risk of STI or HIV acquisition were significantly reduced during the first lockdown. However, reengagement in sexual activity and CAI was rapid in the two months after the lockdown. Resumption of PrEP use after an interruption was more frequent than catching up on HIV/STI testing. Further promoting self-sampling/testing may contribute to mitigating the adverse impact of a succession of lockdowns and periods of easing of restrictions.