Casual sex among MSM during the period of social isolation in the COVID-19 pandemic: Nationwide study in Brazil and Portugal.

Background: The social isolation to which Brazilians and Portuguese are subjected has been affecting their mental and sexual health, decreasing social support and increasing sexual risk behavior and exposure to the SARSCoV-2 virus. In this study we aim to investigate the practice of casual sex and the factors that are associated with this event in the context of the COVID-19 pandemic. Methods: An online survey carried out throughout Brazil and Portugal in April 2020, during the period of social isolation, with a sample of 2361 MSM. The collection took place in meeting apps and Facebook. Findings: There was a high frequency of casual sex (53%) and the use of strategies, without technical or scientific basis, to prevent infection by SARSCoV-2, such as the use of Truvada (12.7%). Among the factors that increased the chance of engaging in casual sex, we highlight: having sex simultaneously with two or more people (aOR = 2.1; 95%CI 1.4 - 3.4); Having sex with a regular and casual partner (aOR = 1.6; 95% CI 0.9−2.8), and only with casual (aOR = 2.5; 95%CI 1.8 - 3.5), using Facebook (aOR = 4.6; 95%CI 3.0−7.2), and cruising, swing houses, saunas or cruising points to get partners (aOR = 5.4; 95%CI 3.2 −8.9), being HIV positive (ORa = 11.7; 95%CI 4.7−29.2), or of unknown serological status (aOR = 1.4; 95%CI 0.7−2.3). In both countries, the longer the period of social isolation, the greater the chance of engaging in casual sex. Interpretation: Despite the great differences between the two countries, in both of them we registered a significant frequency of practicing casual sex, accompanied by dubious strategies to minimize the risk of acquiring SARSCov-2. This indicates that MSM participating in the research, to some degree, continue to be exposed to risky sexual practices for HIV infection and other STIs, but also for COVID-19. Funding: Conselho Nacional de Pesquisa−CNPq, Brazil.