Objective: To evaluate the presence of flu-like syndrome suggestive of COVID-19 in men who have sex with men (MSM) and engaged in casual sex during a period of social isolation. Method: National epidemiological survey, applied in April and May 2020, by adaptation of Respondent Drive Sampling. Results: 1,337 MSM participated in the survey, of which 514 (38.4%) had fever associated with another sign or symptom of...