Lack of consideration of sex and gender in clinical trials for COVID-19

Sex and gender differences impact the incidence of SARS-CoV-2 infection and COVID-19 mortality. Furthermore, sex differences characterize the frequency and severity of pharmacological side effects. A large number of clinical trials are ongoing to develop new therapeutic approaches and vaccines for COVID-19. We investigated the inclusion of sex and/or gender in currently registered studies on http://ClinicalTrials.gov . Only 416 (16.7%) of the 2,484 registered SARS-CoV-2/COVID-19 trials mention sex/gender as recruitment criterion and only 103 (4.1%) allude to sex/gender in the description of the analysis phase. None of the 11 clinical trials published in scientific journals on June 2020 reported sex-disaggregated results. Hence, lack of consideration upon registration does not seem to be corrected during trial execution and reporting. Given the biological relevance and the potential risks of unwanted side effects, we urge researchers to focus on sex-disaggregated analyses already at the planning stage of COVID-19 trials.