Two and a half years into the COVID-19 pandemic, it appears that a majorityTrusted Source of people in the United States have tested positive for the novel coronavirus at least once.
Some have contracted COVID-19 multiple times.
Then there are the “Never COVID” or “Novids” — the people who, despite sometimes living or working in high-exposure environments, have never tested positive for COVID-19.
Researchers are trying to find out why, in hopes of identifying protective factors that could prevent other people from getting sick.
Experts who spoke to Healthline pointed out several major factors that may be helping Novids avoid the illness. Among them include:
Taking safety precautions such as physical distancing and masking
The ability to work from home
“There are probably a lot of different explanations. One of the most important is vaccination,” Dr. Erica Johnson, an assistant professor at Johns Hopkins University in Maryland who chairs the Infectious Disease Board of the American Board of Internal Medicine, told Healthline. “Age, timing, and type of immune response, whether you get exposed before or after vaccination, chronic diseases… all of these go into an individual’s immune response.”
“Some people have been more faithful to mitigation measures, including being vaccinated and boosted, masking, social distancing and avoiding crowds, working remotely, and avoiding travel and venues that increase risk,” David Souleles, MPH, director of the COVID-19 Response at the University of California at Irvine and director of MPH Program & Practice at the UCI Program in Public Health, told Healthline. “These measures all work to reduce the risk of becoming infected and, when layered together, can provide significant protection against COVID-19 infection.”
The role genetics may play
Research from earlier this year suggests that people with a certain genetic makeup may be more susceptible to a COVID-19 infection or serious illness.
However, researchers note that certain types of gene expressions could also provide a protective effect — something that already is known to be the caseTrusted Source with other infectious diseases.
“We seek to understand if the individual genetic makeup of people might explain why some do not contract COVID-19 despite intense exposure to the virus. To test this hypothesis, we use cutting-edge human genetic techniques to study those people who appear naturally resistant to SARS-CoV-2,” Dr. András N. Spaan, a clinical microbiologist at The Rockefeller University in New York and one of the co-founders of the international COVID Human Genetic Effort, told Healthline.
An individual’s immune response to other health conditions and illnesses also may provide some protection against COVID-19, some studies suggest.
For example, researchers reported in a May 2022 study that people with food allergies seemed to have a lower COVID-19 risk.
There also has been “some discussion around whether there is any protective effect from exposure to other coronaviruses, such as the common cold,” said Johnson.
How some Novids have done it
For some Novids, simply not being exposed to people with COVID-19 could be the simple answer to why they have never tested positive.
“As a network security engineer and an entrepreneur, I have the luxury to work from home. I have managed to remain ‘Novid’ even though I am not as careful as I used to be at the beginning of the pandemic,” Andreas Grant, founder of Networks Hardware, told Healthline. “I was super strict about following rules and had some of my own made-up rules as well. Even after I heard that you can’t catch COVID-19 from food, I continued heating every takeaway order I received. For packaged foods, I either didn’t touch them for a specific period of time or washed them. I continued wearing my mask even after everyone else stopped officially wearing them.”
Other Novids, though, may simply have been unaware they had the illness.
The Centers for Disease Control and Prevention estimatesTrusted Source that at least 70 percent of Americans have already had a COVID-19 infection with a number of them having contracted the disease without knowing it.
“It is likely that some people have had COVID-19 and did not know it because they did not test,” said Souleles. “They may have been asymptomatic or had mild symptoms and attributed those symptoms to a cold, flu, or allergies.”
“I had COVID-19 early in the pandemic before vaccines were available,” Erica Susky, a microbiologist and hospital infection-control expert at IPAC Canada, told Healthline. “Even at that time, many people such as myself experienced very mild symptoms.”
“I would have never known, based on my symptoms alone, if I had COVID-19 unless I was PCR tested as part of an outbreak,” Susky noted. “In a regular situation, I would have attributed my symptoms to being overtired, it did not feel much like a cold or flu. If one had a mild illness and tested negative via a [less reliable] rapid antigen test, they may never know with certainty whether or not they had COVID-19.”
The odds of remaining ‘Novid’
A combination of reduced attention to preventive measures such as masking and physical distancing, combined with the rise of vaccine-resistant and immunity-resistant COVID-19 variants such as BA.5, could shrink the population of Novids.
Dr. David Culpepper, clinical director of the telehealth company LifeMD, told Healthline that while wearing a mask and avoiding large gatherings can help people avoid COVID-19, “Most of us know at least one person who has taken all of the available precautions and has still gotten COVID-19.”
“I am not suggesting that you should not wear a mask and take other precautions. You should do everything in your power to reduce your risk of contracting the virus,” said Culpepper. “I’m merely pointing out that some who have contracted COVID-19 have taken a lot of precautions and have just been unlucky. And there is likewise a certain amount of luck involved in those who have avoided it.”
“Now that we are living in an almost post-pandemic world where many of us are vaccinated, I am not as strict as I used to be,” said Grant. “I recently had to start wearing glasses, so I don’t feel like wearing my mask while I have my glasses on. I make an effort to avoid crowded places, but as a movie buff, I can’t help myself from frequently visiting indoor movie theaters. I am not following my made-up rules either, so at this point, I am probably just lucky.”