Three years into the COVID-19 pandemic, most people have contracted the coronavirus at least once. Case numbers, which have roller-coastered throughout the pandemic, spiked especially high when the ultra-infectious omicron variant surged in late 2021 and early 2022, and it continues to spawn more and more transmissible strains.
And yet, some remain who have managed to dodge the virus, or at least haven’t tested positive yet (myself included).
The estimated percentage of people who have contracted the coronavirus ranges from 70% to 90% of the U.S. population, but it’s unclear how many have truly not been infected, as asymptomatic infections and at-home testing have muddied the waters.
Experts say the Bay Area is likely to have a higher rate of COVID super-dodgers than other major metropolitan areas, since a higher proportion of its residents are vaccinated and boosted, and much of its population practiced mitigation factors such as masking or social distancing during the pandemic.
So what is going on with this shrinking subset of COVID holdouts? How have they avoided the coronavirus for so long, and is it inevitable that they will eventually get infected?
Here’s what the experts say, as well as several Bay Area residents who shared their stories.
Avoiding infection
A variety of reasons account for why some people have remained COVID-free, experts say. They include vaccination status, masking, the type of variant circulating, lifestyle choices that lowered overall risk — and just plain luck.
“Certainly, it would be hard to imagine someone who is unvaccinated, or hasn’t been careful, particularly with masking, could remain uninfected,” said Dr. Bob Wachter, chief of medicine at UCSF. “But all of these are risk factors.”
Wachter has detailed his personal COVID strategy throughout the pandemic on his popular Twitter account, and hasn’t yet tested positive, even though his wife contracted the coronavirus in May 2022.
He has been cautious, he said, but good fortune also has played a role.
“I’ve had five vaccine shots, don’t live with small kids, have been relatively careful with masking, and I still attribute the fact that I’ve not had COVID partly to luck,” he said, adding that there are plenty of people who have gotten all their recommended shots and been careful, but nonetheless became infected.
Socioeconomic status can also play a role, said UC Berkeley infectious disease expert and emeritus professor Dr. John Swartzberg, with low-income and minority communities disproportionately hard-hit.
“We know that there is a direct correlation between your income and the chance of getting infected, as well as being hospitalized and dying,” he said.
The transmissibility of the variant also determines infection rates, Swartzberg said, as omicron and its subvariants are far more transmissible than their predecessors.
Asymptomatic infection and immunity
Wachter has taken coronavirus tests whenever he had symptoms, with the results always negative.
“But asymptomatic infection is so common that I think there’s a reasonable chance that I’ve had asymptomatic COVID,” he said. “The fact that my wife had it doesn’t change the odds a ton. We know that the household attack rate is less than 50%, so many people are in my situation: a family member had it, but they didn’t.”
There’s also the possibility that a segment of the population has a natural immunity to the coronavirus.
Early evidence suggested that people with type O blood might be better protected, but Wachter said that theory hasn’t panned out in subsequent studies.
Instead, some individuals may have mutations in their genes that make them resistant to becoming infected with the virus, experts say, just as there are individuals who are naturally “immune” or resistant to HIV and the plague.
UCSF infectious disease expert Dr. Peter Chin-Hong said for COVID, these mutations could involve various receptors:
• ACE2: Where the coronavirus enters the body, and where a mutation in that receptor can make it challenging for the virus to spread.
• Enzymes: Chemicals that speed up reactions in the cells.
• Immune cells: Antibodies or T and B cells.
But it is still unclear how many people have this natural immunity, and Swartzberg said a better understanding is needed of how COVID infects our cells first.
“My guess is that it will be a very small percentage of the population” that is naturally immune to the virus, he said. “People should not assume they cannot become infected. That could be a dangerous mistake.”
Some of the fortunate few in the Bay Area
Bay Area residents contacted by The Chronicle who said they have not tested positive for the coronavirus run the gamut in their pandemic approaches: Some continue to be very cautious, some have fully resumed their pre-pandemic lives, and some are in between.
My husband and I are probably now in the “in between” category — but until fairly recently, we were quite COVID cautious for personal reasons, and have yet to test positive. We got every available vaccine and booster, largely work from home, wore high-quality masks in indoor public settings, ate only outdoors at restaurants and, aside from our wedding last spring, avoided large events and gatherings. I haven’t been on a plane since January 2020.
Susan Taylor, 65, lives in San Francisco and continues to wear a mask on transit and in crowded indoor settings. She and her partner have been following Wachter’s tweets, which she calls invaluable, and will eat only outdoors during COVID surges, then move indoors when transmission rates are low.
“I test when I feel like I’m catching a cold,” Taylor said. “So far, so good. I’m retired, so I haven’t had to go back into an office environment.”
Taylor said she has “traveled extensively,” including to Europe, and has attended performances and the occasional Warriors game.
“I’m continuing to be cautious mostly because I really don’t want to catch COVID, and because I feel like I’ve learned this nifty, easy way to stay healthier,” she said. “Wearing a mask is simple and easy, and I have had hardly any colds or other illnesses, which is a huge bonus.”
Stefanie Lingel, 47, who lives in Los Gatos with her partner, also has yet to test positive for the coronavirus — though she was in New York City at the start of the pandemic, she said, and had to go to the hospital for an injury just as emergency rooms were filling up with COVID patients.
She again avoided contracting the virus when her partner tested positive for the virus last June.
“We live in a very small studio loft,” she said. “He was relegated up to the loft, and I stayed downstairs.” If one of them came down or went upstairs, they masked, and they slept separately.
“We both were testing and I never got it,” she said.
Lingel is vaccinated and has had one booster shot, and has maintained COVID measures throughout the pandemic such as social distancing and masking in indoor spaces, including when going into the office two days a week.
If she does feel a little off, she said, she takes a COVID test, but all have come back negative. She added that she “very rarely gets sick” and doesn’t suffer from any ongoing health problems, and she wonders if that has helped her avoid infection.
Alameda resident Aaron Rubin, 55, lives with his wife, and his teenage son was with them throughout the pandemic, leaving only recently for college. Rubin, a lawyer, worked remotely during lockdown and now goes into the office once or twice a week. He’s fully vaccinated and boosted, and has followed health protocols, loosening up as they lifted.
“My attitude on it from the beginning was that I was just going to do what the health authorities recommend that I do,” he said. “As long as mandates were in place, I complied with those and did what I was supposed to do.”
Once mask mandates ended, he “pretty much stopped wearing a mask” unless he is with someone who is being cautious, he said.
“I’ve been going to concerts, I’ve been on airplanes and was at South by Southwest among crowds of people,” he said, referring to the music festival in Austin, Texas.
He said so far his family has never tested positive for the coronavirus at home, even when they’ve had symptoms. They haven’t gotten PCR tests because Rubin said the symptoms were never severe.
“It could have been a cold, it could have been the flu, it could have been COVID, I have no idea,” he said, acknowledging that at-home tests are not 100% reliable and he could have had a false negative.
Scott Goodman, 34, lives in San Francisco with two roommates. He has had all available vaccine and booster shots, and said he stopped consistently masking indoors in late 2021. He continues to mask only on airplanes and sometimes on transit, and anywhere that requests that masks be worn.
“I’ve gone to a lot of live music, festivals and other public events without much concern,” he said, adding that he has dined indoors “for some time.”
He thinks getting vaccinated as soon as he could and “re-upping with boosters every six months since” has helped, as well as living in a city with “very high vaccination rates, not having any other health issues … and just plain luck.”
“I suppose I could have had it and been totally asymptomatic, but I’d really have no way of knowing that,” he said.
Is COVID inevitable?
While a small percentage of people have managed to stay COVID-free, Swartzberg said the coronavirus will be circulating for a long time, and reinfections are and will continue to be common.
And the ranks of the never-infected will continue to shrink, Swartzberg said.
“Given how transmissible omicron and its subvariants are, it is unlikely people will escape becoming infected,” he said. “How long can we lead a cloistered life?”
If you’re up to date on COVID vaccines and know how to access antiviral therapies such as Paxlovid early on, then “it is safe to loosen restrictions,” Chin-Hong said.
“COVID is going to be part of our lives moving forward for many years, if not indefinitely,” he said. “It is important to use all the tools we have and to have confidence in them … Embrace life zestfully, but responsibly.”
For Wachter, he said if he unknowingly had COVID recently, then he would “feel a bit safer” having that extra immunity.
But since six months have elapsed since he received his bivalent booster, he said his protection against infection has waned, so he’s being a bit more cautious. He’ll opt to dine outdoors when possible, and remove his mask at a party but keep it on in big crowds, on planes and in theaters.
“Since COVID will be around forever, I am taking a few more risks than I used to take,” he said. “I think it’s likelier than not that I’ll get COVID at some point.”
Reach Kellie Hwang: kellie.hwang@sfchronicle.com; Twitter: @KellieHwang