What to Know About COVID Reinfections as BA.5 Cases Continue to Rise

Even if you've had COVID-19 recently, experts say now is not the time to let your guard down.

BERLIN GERMANY - NOVEMBER 28: Shoppers crowd Tauntzienstrasse shopping street on Black Friday weekend during the second wave of the coronavirus pandemic on November 28, 2020 in Berlin, Germany. Christmas season has begun muted in Germany as lockdown measures stay in place and are due to become even stricter in many regions in Germany beginning in December. (Photo by Sean Gallup/Getty Images)
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Fact-checked on July 15, 2022, by Marley Hall, a writer and fact checker specializing in medical and health information.

For the majority of the pandemic, many took solace in believing that once they'd been infected with COVID-19 (or had been immunized), they'd be protected from catching the virus again—at least for a while.

But now, Omicron's BA.5 subvariant is dominating U.S. case counts, not only raising the number of overall COVID-19 cases, but reinfections as well.

The latest data from the Centers for Disease Control and Prevention (CDC) shows that BA.5 makes up 65% of COVID-19 cases in the U.S.; and while the CDC doesn't monitor the reinfections specifically, data from New York State shows that reinfections began ticking up again in June. Meanwhile, an ABC News analysis found that, as of June 8, there have been 1.6 million reinfections across 24 states—and that number may be understated due to at-home testing.

Research published last week in the journal Cell also suggested that "repeat Omicron infections are likely in the population" with the emergence of BA.5, due to its ability to resist neutralization not only from prior vaccination and boosting, but also previous breakthrough infection by the original Omicron (BA.1).

Here's what to know about why BA.5 is causing an increase in reinfections—and how getting COVID-19 multiple times can impact health.

Why Is BA.5 Causing More COVID Reinfections?

It should be noted again that BA.5 is causing an increase in cases overall, not just reinfections. But the driving force behind reinfections, and even breakthrough infections specifically, appears to be BA.5's ability to sidestep prior immunity.

White House chief medical adviser Anthony Fauci, MD, said BA.5 has a "growth advantage" over other Omicron subariants in a Tuesday press briefing. "It substantially evades neutralizing antibodies induced in people by vaccination and infection."

According to infectious disease expert Amesh A. Adalja, MD, senior scholar at the Johns Hopkins Center for Health Security, "[BA.5] has a cluster of immune-evasive mutations." Those mutations essentially make the subvariant less recognizable to the immune system, giving it the ability to evade the immune system's defenses—either by previous infection or vaccination—and reinfect cells.

Eventually though, the immune system will kick into gear—which is why immunity gleaned from past infection and vaccination can protect from severe disease and hospitalization, and even lessen symptoms.

"Reinfections tend to be less severe because you have an immunity wall," Thomas Russo, MD, professor and chief of infectious disease at the University at Buffalo in New York, told Health. "Omicron infections tend to be less severe than infections that happened due to Alpha and Delta strains but the severity of infection doesn't preclude the likelihood of you developing complications [like long COVID]."

However, it's hard to make any broad generalizations since COVID-19 can affect everyone differently. "Some [COVID-19 reinfections] may be less severe, some the same," said Dr. Adalja. "It's not uniform."

How Harmful Is Getting COVID-19 Multiple Times?

Research is still ongoing to parse out just how harmful it can be to get COVID-19 over and over again—but some new preliminary findings suggest that it's much safer to not have reinfections.

A preprint study published in June found that, basically, being reinfected carries greater risks than not being reinfected. Researchers determined that "reinfection contributes additional health risks beyond those incurred in the first infection." That can look like additional respiratory conditions, as well as those that affect other bodily systems, including gastrointestinal disorders, mental health disorders, diabetes, and neurological disorders.

However, experts say to take these findings with a grain of salt. According to Dr. Russo, the study is an association study, and does not provide evidence of causation—meaning, it's not clear whether being reinfected with COVID-19 caused the health issues, or if the participants had underlying health issues all along.

It's also unclear if COVID-19 reinfection increases the likelihood of long COVID. "It's not certain yet if you're well-vaccinated and had COVID previously, if you have a greater or lesser risk of long COVID with repeat infections," William Schaffner, MD, infectious disease specialist and professor at the Vanderbilt University School of Medicine, told Health. "We just don't know yet."

"Reinfections tend to have a lower risk of long COVID, but it is not zero," added Dr. Adalja.

How to Protect Yourself Against COVID-19 Reinfection

Overall, experts warn against letting your guard down after one bout of COVID-19.

"This is a wakeup call," Dr. Russo said. "If you've already been infected once, it doesn't mean you should throw caution to the wind." He also noted that it's "going to be hard to avoid COVID" in the future, given that the virus doesn't seem to be going away.

"The risk will be here 100 years from now," Dr. Adalja added. "People have to decide what risk is tolerable to them."

If you haven't been vaccinated against COVID or aren't up to date on your booster shots, Dr. Schaffner recommends doing that. "It's your best protection," he said. And, if you've had COVID-19 and are considered high risk for complications of the virus, be aware that you could get it again. "You're not off the hook," he said. "You still need to be careful."

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