A new study has found that older men, particularly above the age of 60, are twice as likely to succumb to the COVID-19 infection as women of the same age. According to a New York Times report, published in journal Nature, the researchers found that men produce a weaker immune response to the infection than women.
Women are found to respond with quicker and stronger immune responses. This may be attributed to the fact that their bodies are wired to fight pathogens that threaten unborn or newborn children.
However, it may be be noted that an immune system in a constant state of high alert can also be harmful. Most autoimmune diseases are characterized by an overly powerful immune response, and are much more prevalent in women than in men.
These findings highlight the need for companies pursuing coronavirus vaccines to parse their data by sex and may influence decisions about dosing, Dr Altfeld, an immunologist at the Heinrich Pette Institute and at the University Medical Center Hamburg-Eppendorf in Germany said.
“You could imagine scenarios where a single shot of a vaccine might be sufficient in young individuals or maybe young women, while older men might need to have three shots of vaccine.”Dr Altfeld
Dr William Gruber, Vice President at Pfizer, has stated that companies pursuing coronavirus vaccines have not yet released clinical data analysed specifically by the participants’ sex, ethnic and racial background, but the the Food and Drug Administration (FDA) has requested them to do so.
The Study
The study was led by Dr Akiko Iwasaki, an immunologist at Yale University. The team referred to a sample of 17 men and 22 women who were admitted to the hospital soon after testing positive for the coronavirus. The scientists collected the patients’ blood, nasopharyngeal swabs, saliva, urine and stool every three to seven days, and evaluated their immune response.
The investigation excluded patients on ventilator support and those taking drugs that affect the immune system “to make sure that we’re measuring natural immune response to the virus,” Dr Iwasaki said.
The researchers also evaluated data from an additional 59 men and women who did not meet those parameters.
What They Found
The researchers discovered that women’s bodies produced more T-cells, which are responsible for killing the virus and preventing the spread of the infection. The activation of the T-cells was found to be much weaker in men, and the lag was proportional the severity of the sickness. The older the men, the weaker was the T-cell response.
“When they age, they lose their ability to stimulate T cells. If you look at the ones that really failed to make T cells, they were the ones who did worse with disease.”Dr Isawaki
But “women who are older - even very old, like 90 years old - these women are still making pretty good, decent immune response,” she added.
Limitations Of The Study
The study does have its drawbacks - it was small in size, and the patients were older than 60 years of age on average, making it difficult to assess how the immune system responses vary with age.
The research also could not present a reason for the differences identified between the responses of men and women. Since most of the women were past menopause “it is doubtful that sex steroid hormones are involved,” Dr Klein, a Vaccine Expert at the Johns Hopkins Bloomberg School of Public Health, said.
“We know that age is proving to be a very important factor in Covid-19 outcomes, and the intersection of age and sex must be explored.”Dr Sabra Klein
“The more robust T cell responses in older women could be an important clue to protection and must be explored further,” she added.
(With inputs from The New York Times)
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