Luck or biology? Experts explain why some people seem to dodge COVID infection

In the third year of the pandemic, the vast majority of Americans have been infected with COVID-19 at least once.

In Australia, new research from the University of New South Wales (UNSW) Kirby Institute shows more than 46 per cent of the population had been infected by June.

The lucky few who haven’t been infected have been dubbed “COVID super dodgers” in the US and are part of an evermore exclusive club now that the highly contagious BA.5 Omicron subvariant has taken over as the dominant strain.

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Approximately 60 per cent of Americans had contracted the virus by February, according to the US Centres for Disease Control and Prevention. That was before Omicron subvariants BA.4 and BA.5 started to surge across the nation, now making up more than 80 per cent of cases and fuelling concerns about a potential summer surge.

As both subvariants continue to spread and more infections are reported across the country, Tufts Medical Centre’s Dr Shira Doron, Brigham and Women’s Hospital’s Dr Daniel Kuritzkes and Boston Medical Centre’s Dr Benjamin Linas explained why some people still haven’t been infected with COVID-19 and whether there are biological protections against it during NBC10 Boston’s latest “COVID Q&A” discussion.

Are some people biologically protected from COVID?

There is some historical precedent for biological protections against a virus, experts said, pointing to a small subset of people with genetics that make them resistant to HIV (human immunodeficiency virus). The same could be true for COVID-19, though that has not been scientifically proven.

“In the world of HIV, there’s a group of folks that seem to be protected from infection and, actually, we now understand a lot of that virology and immunology, so it wouldn’t be surprising to me at all if there is a group of people that, for some reason, are protected against infection,” Linas said of COVID-19.

“It’s absolutely possible and it’s important to study that because it teaches you a lot about how the virus works, and even can raise possibilities for therapies in the future.”

Other possible explanations for why people have avoided infection thus far include vaccines, asymptomatic or mild infections, which boost natural immunity, as well as those who took extra precautions, like wearing masks and social distancing.

“I would assume that the majority of people who have not been infected at all are vaccinated people and that some of them may have particularly strong immune responses against the virus that are preventing them from developing symptomatic infection,” Kuritzkes said.

Of course, there’s always the possibility that some people are just lucky.

“I really do think that we’ll find that much of it is luck and that everyone will get COVID,” Doron said. “But there are biological precedents. I think norovirus has a segment of the population that that is immune as well. So it could be — I’m not ruling it out.”

Any of these factors could overlap, experts said, to boost people’s chances of avoiding infection.

“It’s likely a combination of factors,” Kuritzkes said. “First and foremost, it’s probably that a significant number of people who have not been infected are simply taking care.

“They have not exposed themselves to situations where they’re likely to become infected, or they’ve been particularly adherent to wearing masks, and, you know, situations where there might be some risk of transmission.

“There’s an element of luck that they haven’t been exposed to the highly contagious people. And then there may be a biological basis, as well.”