Still, it’s happening. Why is it that there are still people who haven’t had the virus? Do they just never leave the house? While it certainly could be due to taking precautions such as mask-wearing, hand sanitizing and social distancing, new scientific research out of the University of California, San Francisco shows that an estimated 10 percent of the population are asymptomatic to COVID. This means that they actually could have had the virus and just never knew.
Why Do Some People Never Test Positive for COVID?
According to the new research, it is possible to get COVID but never test positive or show symptoms due to a gene mutation. “This was one of the challenges early on in the pandemic—the ability to spread the virus without knowing that you were sick,” says Dr. Roger Seheult, MD, an assistant clinical professor of internal medicine at the University of California, Riverside and a medical advisor to On/Go. Dr. Seheult explains that when the body becomes infected with COVID, the cells chop up the virus internally and present its protein fragments on the cell surface along with a type of protein called MHC1. “MCH1 is on the surface of all cells—except red blood cells—and is the same throughout your body but can look very different between different human beings because there are different versions of the genes which make up this protein,” Dr. Seheult says. He explains that certain people with specific MCH1 patterns seem to present the COVID virus protein fragments better than other versions to the T-cells, which enables the T-cells to destroy the virus faster. This means that the COVID virus gets destroyed in the body faster than it has time to reproduce and affect other cells in the body. “It really doesn’t affect the virus itself other than it takes away its ability to spread in the body,” Dr. Seheult says. “The gene mutation helps people dodge symptoms,” says Dr. Purvi Parikh, MD, an immunologist at NYU Langone. “It basically makes the T cells super immune or have a pre-existing immunity from exposure to other similar viruses so when COVID enters your body it can be neutralized quickly. It’s not foolproof but it gives you a 10 times higher shot of no symptoms.” She adds that this is likely the case for both the original COVID virus as well as its variations such as Omicron and Delta, although more studies need to be done to confirm this. How do you get so lucky? It’s all in the genes. “It can be inherited from either parent, which confers almost a two-and-a-half-fold increased chance of asymptomatic COVID than if they did not have that version of the gene,” Dr. Seheult says. “If someone was lucky enough to get this version of the gene from both parents, that chance increases to over eight-fold.” If someone has this gene mutation, they likely will not show symptoms of COVID and will not spread the virus as readily as those who do not have the mutation.
Other Reasons Why Some People Haven’t Tested Positive for COVID Yet
Just because someone hasn’t tested positive for COVID yet doesn’t mean they should disregard the virus. “There are many other reasons why someone may not have shown COVID symptoms,” Dr. Seheult says. He explains that COVID symptoms can be extremely mild for some people based on either genetics or their health optimization. For example, someone who is immunocompromised is more likely to experience severe symptoms of COVID than someone who is considered in good health. Also, if someone has gotten vaccinated and boosted for COVID and then gets the virus, their symptoms are likely to be more mild. If someone has very mild symptoms, they may not think to take a COVID test. There is also the possibility that someone simply hasn’t gotten the virus yet, especially if they regularly practice social distancing, wear a mask and use hand sanitizer. It’s important to still take COVID seriously; it hasn’t gone away. There are some precautions that everyone can take to protect themselves. “Eating a healthy diet, exercising, getting outside and enjoying the sunshine and fresh air, getting enough sleep, and participating in public health interventions such as vaccination can give you layers of protection now and in the future,” Dr. Seheult says. And that’s good advice whether you have a gene mutation that offers extra protection or not. Next up, here’s what you need to know about treatment for long COVID, if you are still experiencing symptoms months after testing positive.
Sources
Dr. Roger Seheult, MD, assistant clinical professor of internal medicine at the University of California, Riverside and a medical advisor to On/GoDr. Purvi Parikh, MD, immunologist at NYU Langone
