Men are nearly twice as likely to become severely sick and die from Covid-19 compared to women, research has shown. Now, a new study from Yale, published on Wednesday in Nature, gives new clues as to why men fare so much worse with the coronavirus.
It’s the first study to look at the immune response to SARS-CoV-2 by sex, and it found that men produce an overall weaker immune response to the virus than women. “We now have clear data suggesting that the immune landscape in Covid-19 patients is considerably different between the sexes and that these differences may underlie heightened disease susceptibility in men,” senior author Akiko Iwasaki, PhD, told Yale Medicine.
The researchers looked at 98 patients who were older than 60 on average, admitted to the Yale New Haven Hospital with confirmed Covid-19, and compared the initial immune responses in those who recovered from the disease to those who progressed to worse stages. They found that women’s bodies produced more T cells, white blood cells that recognize and eliminate invading pathogens. The male study participants showed much weaker activation of those T cells, which correlated with how sick the men became. Given the findings, the researchers concluded that vaccines will play a particularly important role for men, especially those over age 60.
While the study did not explain why these sex differences in the immune response to the coronavirus exist, the new findings are not overly surprising, considering that scientists know women generally yield faster and stronger immune responses. One possible explanation: In order to protect unborn or newborn children, the female body has a greater evolutionary need to fight pathogens effectively.