Football might be a good metaphor for clinical research on COVID-19. Usually people gather in a sport arena to attend a single match and then change arena for a new match. We might have a strong interest in one match and be absolutely disinterested in another match played in another arena, depending on which teams are playing. The same approach is applicable to a research hypothesis. Each study is usually planned to evaluate a single main aim using a specific design, that is the most appropriate arena (e.g., cohort, case-control, randomized trial,…). However, a different approach sho…Continua su epiprev.it