If you haven’t contracted COVID yet, this might be why

New research reveals why some people have not tested positive.

At the dawn of the pandemic, it was shocking – and terrifying – to hear that someone you knew had tested positive for COVID. While the pandemic certainly still needs to be taken seriously, thanks to the wide spread of COVID vaccines and reminders, for the vast majority of people, contracting COVID is far less frightening than before. In fact, at this point in the pandemic, it’s more surprising to hear of someone who doesn’t tested positive for the virus at some point in the past two years.

Yet it is happening. Why are there still people who haven’t had the virus? Do they ever leave their house? While this could certainly be due to taking precautions such as wearing a mask, hand sanitizing and social distancing, new scientific research from the University of California, San Francisco shows that about 10% of the population are asymptomatic to COVID. This means that they could have had the virus and they just never knew about it.

Related: Should you get the flu shot and the COVID booster at the same time? Doctors share the pros and cons

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 genetic mutation. “That was one of the challenges at the start of the pandemic – the ability to spread the virus without knowing you were sick,” says Dr. Roger Seheult, MDAssistant Clinical Professor of Internal Medicine at the University of California, Riverside and Medical Advisor to Walk/Go.

Dr. Seheult explains that when the body is infected with COVID, cells chop the virus internally and present its protein fragments on the cell surface with a type of protein called MHC1. “MCH1 is found on the surface of all cells – except red blood cells – and is the same throughout your body, but can look very different between different humans because there are different versions of the genes that make up this protein” , explains Dr. Seheult. .

He explains that some people with specific MCH1 profiles seem to present the protein fragments of the COVID virus better than other versions to T cells, allowing the T cells to destroy the virus more quickly. This means that the The COVID virus is destroyed in the body faster than it has time to reproduce and affect other cells in the body. “It doesn’t really affect the virus itself, except it takes away its ability to spread through the body,” says Dr Seheult.

Related: Here’s What Your COVID Immunity Really Looks Like When You Get That Second Booster

“Genetic mutation helps people dodge symptoms,” says Dr. Purvi Parikh, MD, an infectious disease physician at NYU Langone. “It basically makes the T cells super immune or has pre-existing immunity to 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 10x higher rate of being symptom free. She adds that this is likely the case for both the original COVID virus as well as its variants 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, conferring an almost two-and-a-half times greater risk of asymptomatic COVID than if they didn’t have that version of the gene,” says Dr. Seheult. “If someone was lucky enough to get this version of the gene from both parents, that chance is multiplied by more than eight.”

If someone has this genetic mutation, they likely won’t show symptoms of COVID and won’t spread the virus as easily as those who don’t have the mutation.

Related: How long after having COVID are you actually protected from infection? Here’s what you need to know

Other reasons why some people have not yet tested positive for COVID

Just because someone hasn’t tested positive for COVID yet doesn’t mean they should ignore the virus. “There are many other reasons a person may not have shown symptoms of COVID,” says Dr. Seheult. He explains that COVID symptoms can be extremely mild for some people due to genetics or optimizing their health. For example, someone who is immunocompromised is more likely to have severe COVID symptoms than someone considered healthy.

Also, if someone has been vaccinated and boosted for COVID and then catches the virus, their symptoms will likely be milder. If someone has very mild symptoms, they may not think about getting a COVID test.

It’s also possible that someone just hasn’t contracted the virus yet, especially if they regularly practice social distancing, wear a mask and use hand sanitizer.

It is important to continue to take COVID seriously; it hasn’t gone away. There are a few precautions everyone can take to protect themselves. “Eating a healthy diet, exercising, getting outside and enjoying the sun and fresh air, getting enough sleep, and participating in public health interventions such as vaccinations can give you layers of protection now and in the future. future,” says Dr. Seheult. And that’s good advice whether or not you have a genetic mutation that provides additional protection.

Next, here’s what you need to know about treating long COVID, if you’re still showing symptoms months after testing positive.


  • Dr. Roger Seheult, MD, assistant clinical professor of internal medicine at the University of California, Riverside and medical advisor to Walk/Go

  • Dr. Purvi Parikh, MDinfectious disease physician at NYU Langone

Leave a Comment

Your email address will not be published. Required fields are marked *