Why Is Covid19 Killing More Men Than Women?
Reports of an alarming global pattern are emerging: Covid19 is killing more men than women.
In Italy, which has been under a national lockdown for over two weeks, not only do men constitute almost 60 percent of people with confirmed cases of Covid19, but also more than 70 percent of those who have died of the infection are men, stated Istituto Superiore di Sanità, Italy’s top health research agency. The Washington Post reported that as per China’s Center for Disease Control, 64 percent of the lives claimed by the virus were male. Interestingly, in South Korea, while a greater proportion of women tested positive for the virus, the death toll for men was, yet again, higher, at 54%. Dr. Deborah Birx, White House Covid19 Task Force Director, called this a “concerning trend.”
Even during the SARS and MERS outbreaks several years ago, the death rate among men was disproportionately higher than women. “This is a pattern we’ve seen with many viral infections of the respiratory tract — men can have worse outcomes,” Dr. Sabra Klein, a scientist who studies sex differences in viral infections and vaccination responses at the Johns Hopkins Bloomberg School of Public Health, told The New York Times. “We’ve seen this with other viruses. Women fight them off better,” she added.
“Normally with new viruses circulating, everybody gets infected: that’s the important point,” Dr. Bharat Pankhania, Senior Clinical Lecturer at the University of Exeter, told BBC, commenting on the susceptibility of the sexes to Covid19. However, there is a noted disparity in the severity of the infection between males and females.
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“There’s something about the immune system in females that is more exuberant,” Dr. Janine Clayton, director of the Office of Research on Women’s Health at the National Institutes of Health, told The New York Times. A study in the journal Human Genomics suggests that the X chromosome contains a large number of immunity-related genes; because females have two X chromosomes, the theory is that they would have an immunity advantage over males.
Researchers have also raised the possibility of hormonal differences between men and women being responsible for the differences in their immune responses. A study conducted on mice exposed to the SARS-coronavirus showed that males were more susceptible to infection, had a lower immune response, suffered more lung damage, and died at higher rates. Additionally, when the researchers blocked estrogen, or removed the ovaries, in infected females, they were more likely to die. But blocking testosterone in male mice made no difference, leading them to conclude that estrogen may also play a protective role.
In addition, experts suspect that lifestyle differences between the sexes could also account for the discrepancies in death toll. “So in most countries, for example, what we see is that men smoke tobacco and drink alcohol at far greater rates than women do,” said Sarah Hawkes, Professor of Global Public Health at University College London (UCL) and co-director of Global Health 50/50. Experts already believe that decreased lung capacity caused by smoking can make the Covid19 infection more severe in patients. Research shows that while 50% of Chinese men smoke, less than 3% of women do. In Italy, 7 million men smoke as opposed to the 4.5 million women.
“We make these broad sweeping assumptions that men and women are the same behaviorally, in terms of comorbidities, biology and our immune system, and we just are not,” Dr. Klein concluded.