On Jun. 24, 2020, Howard Hughes Medical Institute (HHMI) investigators reported that data from COVID-19 cases around the world suggest that the new coronavirus hits men harder than women. Differences in men and women’s immune responses to the virus may help explain why.

When infected by the new coronavirus, women may mount a more potent adaptive immune response than do men, a new study suggests. By comparison, the male immune response appears to progress less effectively, fostering inflammation thatﾒs harmful to the body.

This study is the first to delve into sex differences in how the immune system defends itself against the virus SARS-CoV-2external link. It could help explain why men can fall more severely ill, says Howard Hughes Medical Institute Investigator Akiko Iwasaki. She and her colleagues posted a preprint describing the study on medRxiv.org on June 9, 2020. Their analysis focused on the immune responses of 93 COVID-19 patients admitted to Yale New Haven Hospital.