People Who Have Had Omicron Don't Necessarily Have COVID Immunity — Here's Why They Should Stay Cautious

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When the latest COVID-19 variant, omicron, hit the U.S. in November, it moved swiftly — cases shot up dramatically, smashing previous records for daily infections and hitting a high on Jan. 10 with 1,433,977.

The highly infectious variant has mutations that had never been seen together in one strain of the virus, meaning that many people who are vaccinated are still getting sick, though with a much milder illness than if they were unvaccinated.

But for the people who have had omicron and recovered — both those vaccinated and unvaccinated — the question now is whether they are immune from getting it again. Infectious disease experts aren't clear on the answer.

"That's what we still don't know," Dr. William Schaffner, professor of preventive medicine and infectious diseases at Vanderbilt University, tells PEOPLE. "A very important unknown is how solidly and for how long natural infection will protect you."

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While past variants, like delta, appeared to provide a strong level of antibody protection for those people who recovered, omicron's milder illness may not lead people to develop enough antibodies to stop them from getting COVID-19 again, either from omicron or another variant.

A recent study, though, provides some hope that people who are vaccinated and then had COVID-19 are well protected. Researchers in Oregon studied fully vaccinated health care workers who were diagnosed with breakthrough infections, and found that they had significantly higher levels of antibodies than vaccinated people who didn't get COVID-19. The study was conducted before the omicron variant emerged but is still a positive sign that people will develop additional natural protection.

And it's important for people who have had COVID-19 to still get their booster, if they haven't (and for people who aren't vaccinated at all to start the process). After COVID-19 illness, they just need to wait until their symptoms have subsided and they are finished with their 10-day isolation period. Between vaccines, a booster dose and any antibodies from COVID-19 infection, they should be well protected against getting it again.

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As the question of how much protection people get from infection lingers, omicron's history in South Africa and the United Kingdom, where it hit before coming to the U.S., has Schaffner feeling "cautious optimism."

"In South Africa, where omicron started, and in England, where omicron spread like crazy, the curve [of cases] went up like a shot. It spiked up, didn't stay there very long, and came down very rapidly," he says, as people got sick, recovered and then found themselves with some level of protection.

"That gives us some cautious optimism that something similar might happen here," he continues. "I don't anticipate that we will have the same sharp downturn because our country is so much larger and much more diverse than England and South Africa. So our gradual fall is likely to be substantially slower as the virus goes from our cities to our suburbs and now to our rural areas, where there are a lot of unvaccinated people."

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But that gradual fall is already starting in the U.S. As Schaffner predicts, daily cases are half of what they were at their peak in cities like New York City and Washington, D.C., and spots like the Northeast and Upper Midwest where omicron hit first. Meanwhile, Southern and Western states like Oklahoma, Utah and Arizona are hitting record levels only now.

The hope, though, is if omicron races through the population and then dies out, the pandemic can finally become endemic, and will be "smoldering" instead of causing the wildfires of the last two years.

"We don't want people to get infected, but the good side of the coin is that it may leave a large portion of the population, at least in the short term, protected against this virus," Schaffner says. "And finally cases will really go down and stay down for a sustained period, and we can move from pandemic to endemic."

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