As a field service representative for a slot machine company, Ryan Alexander, 37, of Louisville, Ky., spends his working hours in casinos, covering a large territory including Norfolk, Va., Indianapolis, and Charlotte. Social distancing in the casinos is not the norm. Despite all this up-close contact with people, he said he is still COVID-free, 3 years into the pandemic.
There was one nervous night when his temperature rose to 101° F, and he figured the virus had caught up with him. “I took a test and was fine,” he said, relieved that the result was negative. The fever disappeared, and he was back to normal soon. “Maybe it was just an exhausting day.”
Mr. Alexander is one of those people who have managed – or at least think they have managed – to avoid getting COVID-19.
He is, some say, a NOVID. While some scientists cringe at the term, it’s caught on to describe these virus super-dodgers. Online entrepreneurs offer NOVID-19 T-shirts, masks, and stickers, in case these super-healthy or super-lucky folks want to publicize their good luck. On Twitter, NOVIDs share stories of how they’ve done it.
How many NOVIDs?
As of March 16, according to the CDC, almost 104 million cases of COVID – about one-third of the U.S. population – have been reported, but many cases are known to go unreported. About half of American adults surveyed said they have had COVID, according to a December report by the COVID States Project, a multiuniversity effort to supply pandemic data.
As the numbers settle over time, though, it becomes clearer that some in the U.S. have apparently managed to avoid the virus.
But some scientists bristle at the term NOVIDs. They prefer the term “resisters,” according to Elena Hsieh, MD, associate professor of pediatrics and immunology at the University of Colorado at Denver, Aurora. Currently, she said, there is much more information on who is more susceptible to contracting severe COVID than who is resistant.
Dr. Hsieh is one of the regional coordinators for the COVID Human Genetic Effort, an international consortium of more than 250 researchers and doctors dedicated to discovering the genetic and immunological bases of the forms of SARS-CoV-2 infection. These researchers and others are looking for explanations for why some people get severe COVID while others seem resistant despite repeated exposure.
Resistance research
In determining explanations for resistance to infection, “the needle in the haystack that we are looking for is a change in the genetic code that would allow for you to avoid entry of the virus into the cell,” Dr. Hsieh said. “That is what being resistant to infection is.”
Part of the reason it’s so difficult to study resistance is defining a resister, she said. While many people consider themselves among that group because they’re been exposed multiple times – even with close family members infected and sick, yet they still felt fine – that doesn’t necessarily make them a resister, she said.
Those people could have been infected but remained without symptoms. “Resistance means the virus was inside you, it was near your cell and it did not infect your cell,” Dr. Hsieh said.
“I don’t think we know a lot so far,” Dr. Hsieh said about resisters. “I do believe that, just like there are genetic defects that make someone more susceptible, there are likely to be genetic defects that make somebody less susceptible.’’
“To identify genetic variants that are protective is a really challenging thing to do,” agreed Peter K. Gregersen, MD, professor of genetics at the Feinstein Institutes for Medical Research at Northwell Health in Manhasset, N.Y. Dr. Gregersen is also a regional coordinator for the COVID Human Genetic Effort.
He suspects the number found to be truly resistant to COVID – versus dodging it so far – is going to be very small or not found at all.
“It may exist for COVID or it may not,” he said. Some people may simply have what he calls a robust immune response in the upper part of the throat, perhaps killing off the virus quickly as soon as it enters, so they don’t get a positive test.
Genetic resistance has been found for other diseases, such as HIV.
“For HIV, scientists have been able to identify a specific gene that codes for a protein that can prevent individuals from getting infected,” said Sabrina Assoumou, MD, MPH, professor of medicine at Boston University, who researches HIV.
However, she said, “we haven’t yet found a similar gene or protein that can prevent people from getting infected with SARS-CoV-2.”
What has been found “is that some people might have a mutation in a gene that encodes for what’s called human leukocyte antigen (HLA),” Dr. Assoumou said. HLA, a molecule found on the surface of most cells, has a crucial role in the immune response to foreign substances. “A mutation in HLA can make people less likely to have symptoms if they get infected. Individuals still get infected, but they are less likely to have symptoms.”
Other research has found that those with food allergies are also less likely to be infected. The researchers have speculated that the inflammation characteristic of allergic conditions may reduce levels of a protein called the ACE2 receptor on the surface of airway cells. The SARS-CoV-2 virus uses the receptor to enter the cells, so if levels are low, that could reduce the ability of the virus to infect people.
The COVID Human Genetic Effort continues to search for participants, both those who were admitted to a hospital or repeatedly seen at a hospital because of COVID, as well as those who did not get infected, even after “intense and repeated” exposure.
The number of people likely to be resistant is much smaller, Dr. Hsieh said, than the number of people susceptible to severe disease.