Is there sufficient scientific evidence to rule out the use of hydroxychloroquine for postexposure prophylaxis of COVID-19?

Since the beginning of the COVID-19 pandemic, the use of hydroxychloroquine (HCQ) has been surrounded by a lot of controversy, both scientific and non-scientific. This has continued with the publication of two trials of HCQ for post-exposure prophylaxis of the infection, which concluded that HCQ is not efficacious to prevent SARS-CoV-2 infection, and their results are influencing public health decisions.We have carried out a comprehensive post-hoc analysis of the statistical power of the two trials, which shows that their power to detect an effect of HCQ in preventing COVID-19 is low, not only for their observed effect size, but also for other clinically important levels of efficacy, and therefore both studies are inconclusive.