As the first wave of COVID-19 vaccines enter the market, and global immunisation programmes are implemented, the time is right to remind researchers and regulatory agencies of the critical importance of including biological sex as a variable in trial data analysis and reporting. The phase 3 Oxford–AstraZeneca trial interim report indicates more participation from women, which the investigators attribute to a recruitment focus on health-care workers, but they have not yet reported or discussed how biological sex could influence the data. Future reporting of sex-disaggregated data and a discussion of how sex factors influence the trial outcomes would benefit regulatory and public decision making and the design of mass vaccination programmes.

Lavanya Vijayasingham, Evelyne Bischof, Jeannette Wolfe on behalf of the Gender and COVID-19 Research Agenda-setting Initiative. Sex-disaggregated data in COVID-19 vaccine trials – The Lancet, March 05, 2021.