Can you catch COVID-19 twice in 90 days? Here’s why it’s more likely than ever

Looking at the state of COVID-19 in the United States, Mansoor Amiji, Distinguished Professor in the Department of Pharmaceutical Sciences at Northeastern, invites you to think from the perspective of a virus. What does he want ? What should it do to find new hosts or to re-infect old ones?

The answer, he says, lies in spike proteins, the part of a virus that attaches to the receptor on a host cell. Under the pressure of natural immunity and other countermeasures to its survival, the COVID-19 virus mutates these peak proteins randomly, creating new variants that are more transmissible than the previous ones.

This development makes COVID-19 similar to other viruses we have seen. “It really is the natural course of a virus,” says Amiji.

It’s also why you’re more likely to get COVID-19 twice now than just four months ago. New variants like BA-4 or BA-5, which were unknown earlier this year, are now circulating in the United States, and they may not be prevented by vaccines, boosters, or the antibodies you develop when you are infected. by another variant.

For example, if you’ve been infected with the BA-2 subvariant, that doesn’t prevent you from being infected with BA-4 or BA-5, says Neil Maniar, professor of practice in the Department of Health Sciences. Maniar says each subvariant of COVID-19 tends to be more transmissible than the last, and protection against one does not guarantee protection against the other.

“It doesn’t mean we have to fear reinfection,” Maniar says, “but it does mean we have to keep in mind that just because you got COVID once you don’t have it doesn’t mean you don’t have it anymore. within one year.” months or two months or three months, because there are these different sub-variants floating around.”

Despite this development, the Centers for Disease Control and Prevention still does not recommend testing for COVID-19 within 90 days of recovery from infection.

“If you have tested positive for COVID-19 with a viral test within the previous 90 days and have subsequently recovered and remain asymptomatic, you do not need to self-quarantine or get tested after a close contact,” reads the CDC’s website.

The reason is, says Maniar, that a PCR test can still detect traces of the virus even after someone is no longer symptomatic or infectious. This can lead to a false positiveeven when an antigen (or “rapid”) test is negative.

“These viral particles can be detected for up to two or three months,” he says.

When writing the recommendation, it was also thought that antibodies developed during infection could prevent you from being re-infected within 90 days. But that’s not really the case, says Maniar.

“The idea that if you get infected, you don’t necessarily have to worry about getting reinfected for three months, doesn’t necessarily apply anymore,” he says.

Returning to the “new normal” – mask-less workspaces and airplanes, for example – may increase the likelihood of reinfections from different variants.

“We’re really starting to get back to a much more normal pace of life compared to earlier this year,” Maniar said. “It’s really a good thing.”

That means we have resources at our disposal, like vaccines and masks, to come together in relative safety, he says. However, “the probability of being exposed increases”.

Fortunately, as the variants tend to become more contagious, they also tend to become less potent. Amiji says COVID-19 subvariants typically cause more upper than lower respiratory problems, making symptoms less severe. And for those who have been vaccinated and given boosters, symptoms tend to be even milder or non-existent. This reinforces the importance of getting vaccinated and boosted. Amiji hopes that one day COVID-19 boosters will combine with flu shots, and that it will be easy to get both at the same time every year.

But hospitalizations are still happening, especially among subsets of the population who are at higher risk, so it’s still important to take preventive measures even as we begin to enter what Amiji calls an “endemic” phase of the pandemic.

To help stop the spread, Amiji recommends getting tested if you have symptoms and if a rapid test– which is less sensitive than a PCR test – is positive, you must self-isolate and wear a mask indoors. How long it takes to test negative after being infected varies from person to person, he says, but it’s important to keep testing in order to make informed decisions. “It’s when you start to test negative that you could potentially be less infectious,” he says.

Maniar compares measures like these to wearing a seatbelt every time you get into a car. “We all need to keep thinking about others around us and thinking about what we need to do to protect ourselves.”

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