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Editor’s note: For updates on the most recent dominant subvariant, read more about BA.5 here.

One thing about entering the third pandemic year (yep, you read that right) is that we know enough about Covid now to know what we don’t know. So when a variant pops up that threatens to take over the dominant strain, we know exactly which questions to ask. Which is the good part. The tough part? We don’t have all the answers yet.

That’s the case with the BA.2 variant, a subvariant of Omicron (which was originally dependent on the strain labeled BA.1), which first appeared in December and was nicknamed ‘the stealth variant’ as it was harder to detect. But that was when the Delta variant and BA.1 were competing for the top spot—and BA.2 looked very similar to Delta on PCR tests. Now that Omicron is the dominant strain and Delta is much more rare, it’s much easier to distinguish between BA.1 and BA.2. And now, cases of BA.2 are starting to pop up across the country, mostly in the Northeast. The stealth variant has stepped into the sun.

Cases of the BA.2 variant are on the rise

According to Centers for Disease Control and Prevention (CDC), BA.2 cases have consistently risen in the U.S. since the strain was first discovered, now accounting for 68.1% of new cases. A separate strain, BA.2.12.1, now accounts for nearly 29% of new cases.

Because case numbers sharply increased throughout February and March in the U.K. and Europe, often a bellwether for what will eventually take place in the U.S., experts have been closely monitoring BA.2’s status. 

The U.S. is now starting to see an uptick in cases, too. Dr. Anthony Fauci, the Biden administration’s medical advisor, said on ABC’s “This Week” that this is “no time at all to declare victory, because this virus has fooled us before and we really must be prepared for the possibility that we might get another variant.” 

But will the BA.2 variant cause a surge the same way Omicron did? Well, that’s one thing we still don’t know. Here’s what we do know.

We know that BA.2 is more transmissible than BA.1

The World Health Organization (WHO) reports that BA.2 is more contagious than the original Omicron strain (BA.1), but at a level that’s not quite as high as the difference in transmissibility between BA.1 and Delta. Omicron’s BA.1 was thought to be nearly 2.5 times as contagious as Delta, whereas BA.2 is estimated to be 30% to 50% more contagious than Omicron.

We know that BA.2 is less severe

Omicron proved to be more contagious but less mild than previous strains, with a reduced impact on the lungs. But because it still spread so quickly, we saw drastic surges in hospitalizations and deaths, simply because so many more people were infected. 

Thankfully, it seems that BA.2 causes less severe illness than previous strains. Initial studies provided more clues: researchers in both the U.K. and Denmark found that BA.2 does not carry a higher risk of hospitalization than BA.1.

We do know that kids were 5 times more likely to be hospitalized with Omicron than with previous strains. This could still be the case with BA.2, especially as just 28.5% of children ages 5 to 11 have been fully vaccinated at this time, and kids under age 5 are still ineligible for vaccination.

We know that vaccines still work in preventing severe disease

Even though breakthrough infections were common with Omicron, vaccines were still protective against severe disease, and experts believe that to be the case with BA.2. Vaccines may be less effective at preventing illness in general, but getting a booster can offer significantly more protection—and help keep you out of the hospital. 

If you or your child have not yet been vaccinated, consider starting your vaccine series now, as that will allow enough time to build up immunity (to be fully vaccinated means two weeks after the second dose) before there is a sharp increase in case numbers. 

It’s important to note that the CDC has updated its guidelines to recommend delaying the second shot until 8 weeks after the first (as opposed to three with Pfizer or four with Moderna) for those ages 12 and up, in an effort to both reduce the risk of myocarditis and improve vaccine efficacy. 

We know that previous infection offers some protection in kids

But we don’t know how much protection. A recent study from the University of Texas published in Pediatrics shows that kids infected with Covid continue to have antibodies to the virus upwards of 6 months after initial infection. But whether the level of antibody protection is high enough to prevent future infection, researchers still don’t know.

Authors of a related commentary note that while this study provides “some reassuring data” in regards to children’s antibody response, “it should not provide false reassurance” to parents hesitant to get their children vaccinated. 

“Natural infection with coronaviruses confers only transient humoral immune response; in contrast, mRNA vaccines have less decay in antibody responses over time and may also result in cell-mediated immunity,” say the authors of the commentary. Vaccination is still the best way to offer virus protection to your child. 

What you can do now

As Dr. Fauci stated, now is not the time to completely let down your guard. But it’s also not time to panic. We’ve been in this spot before—we know how to adapt.

Get outside: Luckily, spring is here, which means you may be able to move more activities and events outdoors to reduce the risk of transmission. 

Consider masking: Wearing a mask in public places may be warranted if you determine that your personal level of risk is high (or if your kids’ level is high), especially if you or your child are unvaccinated or it’s been more than 5 months since your last shot or booster. Though the CDC has lifted masking recommendations, that stipulation is based on areas where hospitals won’t risk reaching full capacity—it’s not based on levels of community transmission. 

Keep up with hand hygiene: Washing your hands after touching public surfaces is a good way to prevent disease, especially in little kids. 

Upgrade your masks: ​​Stock up on disposable masks with a high level of protection, like KF94s or KN95s, for both kids and adults, rather than reusable cloth masks.

Self-test at home: Stock up on Covid tests (you can get another round of free tests from the U.S. Postal Service) and isolate if you have any symptoms of Covid or a positive result.

A version of this article was originally published on March 22, 2022. It has been updated.