With the BA.5 omicron subvariant leading to a rise in reinfections, even for those who may have already had omicron, many are wondering how quickly they could get COVID again following an infection.
While many experts say the exact timing remains unclear and dependent on each individual, cases are being reported of reinfections in as early as one month.
"We don't know know exactly how soon, but people have been recorded to get the infection as soon as four weeks after having a previous infection," said Dr. Sharon Welbel, director of hospital epidemiology and infection control at Cook County Health.
Welbel said that current reinfections could be related to either waning immunity from a previous infection or from vaccinations, depending on if a person has had a booster shot and when. For that reason, Welbel said it's possible some could contract the virus again even earlier than one month post-infection.
"It could even be sooner," she said. "I would think, you know, depending on one's immune system, on their level of antibodies - to either the vaccine or a previous infection - but because, you know, we do not become immune to this from our vaccine or from a previous infection to any of the variants that we have already experienced ... I don't see why somebody couldn't even get it as soon as two weeks later. Have I been seeing that? No. Have I been seeing that talked about? No. But definitely have seen people within a month."
The question over how protected someone is following a COVID infection has come with varying answers since the pandemic began.
Chicago's top doctor noted that while the omicron variant itself marked a distinct shift in reinfections, evading natural immunity from infections with previous strains, BA.5 has similarly evaded immunity from even other omicron infections.
"All of the variants prior to this, we were not seeing a lot of reinfection with the current variant," Chicago Department of Public Health Commissioner Dr. Allison Arwady said. "So we saw people who had alpha or delta in the past be relatively protected, but potentially get infected with omicron. Everything has been omicron since January, to be clear - all of these subvariants are different versions of omicron. BA.4, BA.5 is the first one where we're seeing some reinfection even of people that had a prior version of omicron. So that is different."
Arwady said while it's still not likely someone will be reinfected if you had COVID recently, "we are seeing some more of these infections."
"Especially if you're counting on an omicron infection from six months ago, like don't be counting on that," she said.
Aside from being even more contagious than previous variants, scientists have been tracking a mutation in BA.4 and BA.5 that could help it evade some immunity and cause reinfections.
A genetic trait that harkens back to the pandemic's past, similar to what is known as the “delta mutation," appears to allow the subvariants "to escape pre-existing immunity from vaccination and prior infection, especially if you were infected in the omicron wave," said Dr. Wesley Long, a pathologist at Houston Methodist in Texas. That's because the original omicron strain that swept the world didn’t have the mutation.
This genetic change is bad news for people who caught the original omicron and thought it made them unlikely to get COVID-19 again soon. Although most people don't know for sure which variant caused their illness, the original omicron caused a giant wave of cases late last year and early this year.
Long said lab data suggests a prior infection with the original omicron is not very protective against reinfection with the new mutants, though the true risk of being reinfected no matter the variant is unique to every person and situation.
However, COVID-19 vaccinations have continued to prevent severe hospitalization and death, experts said.
Arwady noted that while much is still unfolding surrounding the omicron subvariants BA.4 and BA.5, she doesn't believe the incubation period is changing, but some people are staying positive for longer.
"I wouldn't say the incubation period is shorter. ... It's been getting shorter compared to what the original was, but we are seeing people often have just upper respiratory symptoms or having a cold. They're having sore throat sometimes, they're having fever or not seeing a lot of that severe illness - especially in people who are up-to-date with vaccine because the secondary part of your immune system kicks in and helps - but we're seeing people can stay positive for a little longer," she said.
Welbel continued to urge people to take precautions as the new mutations continue to spread.
"We know there's very little mitigation happening publicly but, you know, wearing a mask indoors all the time is going to help - a well-fitted mask, so the N95 or KN95 and above," she said. "And having your vaccines up-to-date. Even outside I recommend wearing a mask if you're going to be in close contact with people."