Around 80% of the participants sent in their tests. None of 1868 people in the control group tested positive, and only one of 1896 gymgoers did—but that person had not yet been to the gym and likely was infected elsewhere, the researchers report in a preprint posted to medRxiv. Kalager and colleagues also searched Norway’s comprehensive public medical records and found that none of the participants in either group had been admitted to a hospital with COVID-19–related complaints.