Coronavirus Pandemic, Featured
Although COVID-19 is known to be a deadly virus with no particular preference for gender, age, race and status, but many studies have shown that the virus tends to be more severe and deadly with men than in women and the elderly
By Benprince Eze
SINCE the coronavirus, COVID-19, broke out in 2019 and classified as pandemic by the World Health Organisation, WHO, in 2020, the victims of the deadly virus appear to be more of men than women and the elderly. But medical doctors are trying to figure out why the virus attacks more men than women. Though no research result has come out with specific reasons for this development, but It is possible that the sex hormones estrogen and testosterone play a role according to previous research on respiratory illnesses.
Perhaps it is because the X chromosome, which women have two of, but men have only one, has a larger number of immune-related genes, giving women more robust immune system to fight off the coronavirus, SARS-CoV-2. Maybe the virus is hiding in the testes, with abundant expression of ACE2 receptors, the portal that allows SARS-CoV-2 into cells.
Uncovering the real reason is, of course, imperative because it could help improve patient “outcomes during an active public health crisis,” according to an editorial published on April 10 in the Western Journal of Emergency Medicine, WJEM.
However, since the first known COVID-19 case was reported in China late last year, countless studies have shown that the disease tends to be more severe and deadly in men than in women.
For instance, in an analysis of 5,700 COVID-19 patients hospitalized in New York City, just over 60% were men, according to an April 22 study published in the journal JAMA. What’s more, “mortality rates were higher for male compared with female patients at every 10-year age interval older than 20 years,” the researchers wrote in the study.
Furthermore, of the 373 patients who ended up in intensive care units, 66.5% were men, the JAMA study reported. Results are similar in other studies. When the WJEM editorial was published in early April, the authors noted that between 51% and 66.7% of hospitalized patients in Wuhan, China, were male; 58% in Italy were male; and 70% of all COVID-related deaths worldwide were male. In one large study of more than 44,600 people with COVID-19 in China, 2.8% of men died versus just 1.7% of women.
The sources of the stronger female immune response can be found in both the innate and adaptive immune systems, says Sabra Klein, a virologist at the Johns Hopkins University Bloomberg School of Public Health. The innate system provides the first response against a virus, while the adaptive system’s contribution is slightly delayed by the time needed to ramp up antibody production against a new intruder.
One component of the innate immune system is called toll-like receptor 7. This protein can recognize molecules found on viruses, thereby outing the pathogens as foreign. The gene for toll-like receptor 7 resides on the X chromosome. Because females have two copies of the X, the body silences one (SN: 4/8/03), allowing for the right “dose” of X chromosome genes.
But some genes escape the shut down, and there is evidence that this is true for the gene for toll-like receptor 7, researchers reported in Science Immunology in 2018. That can lead to more of the protein being made; giving females more guards look out for intruders.
Having more toll-like receptor 7 can help jump start and enhance the next steps of the innate immune system. “You want fast recognition, you want fast responses,” Klein says.
“This is how you start to activate the army of immune responses that are going to be needed to clear an infection.” One of those steps is the release of interferons, proteins that direct major factions of the body’s immune response. In studies that measure levels of interferons in blood or in cells grown in a dish, researchers overall see “greater production of these interferons in females as compared with males,” says Klein.
Emmanuel Enang, a doctor with Federal Medical Centre, FMC, Abeokuta says that One major variable in severity of COVID-19 is age, but it can’t explain the sex bias seen globally because the increase in male fatality rate is the same in each age group from 30 to 90+. “Women live on average six years longer than men, so there are more elderly women than men in the vulnerable population.
“The other major factor is the presence of chronic diseases, particularly heart disease, diabetes and cancer. These are all more common in men than women, which might account for some of the bias. But then we must ask why men are more vulnerable to the diseases that put them at greater risk of COVID-19,” he said.
According to him, men and women differ in their sex chromosomes and the genes that lie on them. “Women have two copies of a mid-sized chromosome (called the X). Men have only a single X chromosome and a small Y chromosome that contains few genes.
“One of these Y genes (SRY) directs the embryo to become male by kick-starting the development of testes in an XY embryo. The testes make male hormones and the hormones make the baby develop as a boy. But it all tends down to the bigger problem for men, which are the male hormones unleashed by SRY action. Testosterone levels are implicated in many diseases, particularly heart disease, and may affect lifespan.
Men are also disadvantaged by their low levels of estrogen, which protects women from many diseases, including heart disease. Male hormones also influence behaviour.
Testosterone levels have been credited with major differences between men and women in risky behaviours such as smoking and drinking too much alcohol, as well as reluctance to heed health advice and to seek medical help, Enang said.
For Christopher Chime, a genetic doctor based abroad, this has been in study for months since the inception of this deadly pandemic disease. “I think many proteins that work together to defend the body against viruses do not operate exactly the same way in males and females. Those biological differences, driven by sex hormones and genes, may be guarding some women from the deadliest complications of COVID-19.
“Females mount a stronger immune response than males, studies have found. This makes women overall less susceptible to viral infections than men, although how each individual fares is another matter. A stronger immune response also means females are more likely to develop autoimmune diseases, when the immune system attacks one’s own tissue; conversely, a toned down immune response makes males more prone to having a host of malignant cancers. Lastly, I strongly believe women have more life span than men and have stronger immune system to fight disease than the men,” he said.
Elvis Okafor, another medical practitioner, said that it could be as a result to exposure as the men are the bread winners of different homes. “They go out more often and as such are exposed to the virus. We have higher consumption of alcohol and drugs, which weaken the lungs and liver. These can simply be said to have more effects in men and cause of impaired damages,” Okafor said.
– May 1, 2020 @ 15:35 GMT |
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