Known for being physically identical people, twins are an interesting research subject for scientists who have seen how the coronavirus has affected each sibling in different ways, contrary to the generalized idea that they suffer the effects in equal measure by sharing their genes .
Sisters Kelly and Kimberly Standard from Michigan, United States had that thought. They believed that when they caught COVID-19 almost a year ago their experience would be identical, however the 35-year-old women were in for a huge surprise.
Kelly was hospitalized less than a week since she was diagnosed and did not wait to be discharged alone and go home while Kimberly spent several weeks connected to breathe.
Considering cases like this, scientists have aimed to analyze cases of twins to better understand how the virus affects their bodies, which share genes and often, also, lifestyles.
Thanks to records of twins in places like the United States, Europe and Australia, experts have been able to delve into the information that confirms that genetics can affect the symptoms that infected patients experience, according to The New York Times .
Other factors such as the environment and even chance also alter the outcome, the researchers suggest, and this situation extends to identical twins, where immune systems can differ and move away from each other over time.
Dr. Mishita Goel who attended the Standard sisters was surprised by their reaction, considering the differences in health in them. Although both are overweight and have a history of metabolic conditions, everything pointed to the twin with asthma and diabetes having a better chance of going to intensive care . However, the one in the worst health was Kelly, precisely the one who suffered the least from the virus.
Tim Spector, an epidemiologist and director of the TwinsUK registry based at St. Thomas Hospital in London, conducted a study where his results suggest that symptoms such as fatigue or fever caused by the virus are the product of a measurable genetic influence.
In contrast to the Standard twins, Kasey Miller and Krista Burkett were infected after a celebration of Thanksgiving (an American holiday that takes place at the end of November) and their symptoms were identical except that they occurred with a week Of diference.
The 28-year-old women in Ohio developed fever, back pain, and fatigue. “Honestly, it was kind of nice for her. She could see exactly what would happen to her, ”Miller said of her sister.
In addition to genetic, behavioral factors and the diseases that each individual has, experts indicated that each person’s history of other types of coronavirus, such as exposure to previous common colds, can alter how their body is affected if they are infects of covid-19 .
In turn, they ensure that the amount of virus that is ingested is also related to the severity of the symptoms that will appear.
“It’s the difference between your immune system actually being able to squash the infection or having a harder time fighting it if all your cells are infected at the same time,” said Juliet Morrison, a virologist at the University of California.
Marena and Vivian Herr fell ill with coronavirus after a Halloween party and their symptoms were very different. Marena lost her sense of taste and smell, which she has not yet recovered. For her part, Vivian felt she was battling a debilitating flu-like illness.
Bobby and Billy Ford hung out together even before they were born one after the other Jan. 21, 1962. USA TODAY
The identical twins were inseparable as youngsters growing up in Williamsburg, Virginia, where their father started an auto repair shop after fixing helicopters for 20-plus years in the Army.
Anita Pepper, a developmental biologist and vice president of the Wistar Institute in Philadelphia, said that little change alters the way people respond to infections. In turn, his sister Marion Pepper, an immunologist at the University of Washington, complemented by explaining that the randomness of the processes makes them impossible to replicate from one person to another.
Thus, the differences between identical organisms are increased by external factors such as their exposure to the virus, their previous illnesses, lifestyles and close circles. It should be considered that although two people have received the same upbringing and share spaces, they may present differences, in addition that their behaviors may be divided over time.
In addition, the genes of each brother are not completely identical, since they present minimal differences since they are embryos. Then, from childhood and adolescence, the gulf of differences between the two bodies is increased, according to the different microorganisms that come into contact with them .