Women are under-represented as research participants in most interventional and observational studies on COVID-19. Main outcome data from interventional and observational studies are rarely reported disaggregated by sex. Sex and gender differences are inadequately examined in the analysis of the data. Lack of sex and gender analysis are seldom justified, and gender implications rarely discussed. There is a renewed rationale for strengthening the reporting of sex and gender dimensions in clinical research using the Sex and Gender Equity in Research guidelines.