Is the omicron BA.2 variant a concern?

March 29, 2022
concerns over COVID-19 variants. Scientists at the CDC study the virus that causes COVID-19
Scientists at the Centers for Disease Control and Prevention (CDC) load samples from patients into an automated instrument as they study the virus that causes COVID-19. The newest question for researchers and the public is whether the omicron BA.2 variant is a concern. Photo by James Gathany for the CDC.

The BA.2 variant, the newest COVID-19 strain, continues to account for a high percentage of cases in the United States. Is BA.2 a concern? And how worried should you be?

We consulted with infectious disease and COVID-19 expert, Dr. Thomas Campbell, to answer your questions about BA.2 and other variants.

Campbell ran clinical trials for COVID-19 vaccines at UCHealth University of Colorado Hospital on the Anschutz Medical Campus. He is also a professor of medicine and infectious diseases at the University of Colorado School of Medicine.

We’re all ready for the pandemic to be over, but now we’re hearing about the new BA.2 variant. What is BA.2 and should I be concerned?

“The new BA.2 variant is another version of omicron. It behaves very much like the previous version of omicron,” Campbell said.

And, yes, unfortunately we should be concerned about BA.2, he said.

That’s because it’s even more infectious than the original omicron variant, which itself was far more infectious than delta and previous COVID-19 variants.

“Each iteration of these variants is more and more infectious,” Campbell said.

While the original omicron variant has not caused people to get as severely ill as the delta variant, BA.2 could be dangerous for unvaccinated people, vulnerable older people whose antibodies have declined and people who are immunocompromised.

Campbell says we’re now in a “calm in the storm,” with lower hospitalizations and deaths. But he predicts that this relatively quiet time won’t last. And sadly, the pandemic is not over yet.

“We will likely see a spike in cases again, but I hope that we don’t see a big spike in hospitalizations,” Campbell said.

Why is BA.2 a concern if many people are vaccinated or have previously gotten sick with COVID-19?

dr. Thomas Campbell
Dr. Thomas Campbell is an expert on COVID-19 and other infectious diseases. He shared his expertise about the BA.2 variant and whether you should be concerned about it. Photo: UCHealth.

The problem is that millions of people still are vulnerable to severe illness. That’s because many are either unvaccinated, haven’t gotten booster doses or their immunities from an infection have waned.

While about 80% of people in the U.S. have had at least one vaccine dose, that still leaves millions who are not up to date on vaccines. The U.S. population is about 331 million. So, if 20% of people are unvaccinated, that’s 66 million people.

Of course, some of these unvaccinated people already have gotten COVID-19 and should have some natural immunities that could provide protection. But studies have shown that immunities — both from vaccines and prior infections — wane over time.

And there are some people who never had vaccines or COVID-19.

“There still is a substantial portion of the population, perhaps around 10-to-15%, who have no immunities. They have not been vaccinated and they have not been infected yet. Those individuals continue to be at high risk,” Campbell said.

If I had COVID-19 already, but am not vaccinated, am I at risk of getting BA.2?

Yes. Anyone who is unvaccinated could get very sick with BA.2 even if they previously have gotten sick with COVID-19.

“People who have recovered from pre-omicron strains like delta, alpha or the original Wuhan strain are at risk. Immunities from a previous infection do not offer high protection against omicron or BA.2,” Campbell said.

Who is at the greatest risk if they get COVID-19 from BA.2 or any other variant?

Throughout the pandemic, unvaccinated people have been at the greatest risk. That’s still true.  In addition, other groups have been especially vulnerable.

“People who are older and those who have underlying health conditions are most at risk for a bad outcome, including hospitalization and possibly death,” Campbell said.

Who is at intermediate risk if they get BA.2?

“People who have been vaccinated, but have not gotten the booster shot are at intermediate risk,” Campbell said.

Why? The key reason is that as the variants have developed, vaccines have become less effective at preventing infections, although they are still highly effective at preventing hospitalizations and deaths.

“There’s still a huge number of people who are at intermediate risk because of waning immunity after a booster or who haven’t gotten a booster or are not vaccinated at all and recovered from a pre-omicron variant,” Campbell said.

Vulnerable people who have not fared well with COVID-19 infections — including older people, immunocompromised people and pregnant women, for example — could still get very sick with BA.2.

“One or two doses of vaccines do not protect very well against symptomatic infection with either the original omicron variant or BA.2,” Campbell said. “A booster dose protects well, but fades over time.”

Campbell, himself, was one of the people who was fully vaccinated and had a booster and still got sick with omicron. He was able to recover at home and experienced relatively mild symptoms.

“It wasn’t too bad because I’ve been vaccinated and boosted. If I hadn’t had any of the immunity from vaccines, I probably would have been very ill,” he said.

What should people do to stay well?

Anyone who isn’t vaccinated should get vaccinated. And those who are vaccinated, but haven’t gotten booster doses should also do so as soon as possible.

Campbell’s message is clear: get up to date on your vaccines to prevent COVID-19.

“It’s estimated that in the U.S., only about 50% of people who are eligible for a booster have received one,” Campbell said.

Are you concerned that mask mandates have been lifted and few precautions are in place now as the new BA.2 variant is spreading quickly?

Campbell is realistic. He understands why politicians and public health leaders have loosened restrictions. Leaders in all 50 U.S. states have lifted mask mandates. Two years into the pandemic, the majority of people have little desire to return to restrictive measures.

This means that BA.2 and any future variants will be able to spread more easily.

“Everything is wide open and no one is wearing masks. So, all the public health measures that we had in place to temper the spread of the virus during previous waves are no longer there. That means that the infection will spread faster,” Campbell said. “At the same time, we have more infectious variants so they’re going to spread more easily from person to person.”

So, individuals will need to evaluate their choices.

If you are at high risk due to a pre-existing health condition, continue to be cautious and wear a mask in crowded indoor settings.

How long do immunities to COVID-19 last?

While scientists don’t know exactly how long immunities last, Campbell said we can learn a great deal from other coronaviruses that cause the common cold and have been infecting humans for millennia.

“There are four other coronaviruses that infect us,” Campbell said. “Virtually 100% of us are infected with all four of them at some point in our life. Most of us are infected multiple times with each one of them.”

Researchers have done experiments in which they have deliberately infected people with the common coronaviruses, then measured their immunities.

While people had immunities shortly after their infections, months or years later, the immunities are often gone.

“They’re completely infectible with the same virus,” Campbell said. “So, immunity after recovering from a coronavirus is not lifelong.”

But the news on coronavirus immunities is not all disappointing.

“Although immunities don’t protect against infection. They do seem to protect against serious illness. So, in most people, these coronaviruses only cause the common cold,” he said.

“We can mimic this effect with vaccines and by boosting so that the virus causes only a relatively mild illness,” Campbell said. “Even with boosting, it’s not 100%. You get the best protection in the three to four months after a booster.”

Should people who had omicron be concerned about an infection from BA.2?

Campbell said there have been a handful of documented cases of people who recovered from omicron and became re-infected with the newest variant.

“It’s very uncommon, but it’s not zero,” he said.

What about additional booster shots? Will healthy people need a fourth COVID-19 vaccine dose and will immunocompromised people need an extra booster as well?

Yes. Leaders at the Food and Drug Administration (FDA) have authorized additional booster doses of Pfizer and Moderna COVID-19 vaccines for everyone ages 50 an older, along with some other immunocompromised people.

Health officials authorized the additional boosters because immunities are waning and they want as many people as possible to be protected before the next wave of infections hits.

Campbell encourages people to follow the FDA guidance.

“Everyone should get fully vaccinated and boosted,” he said.

Health officials in Israel have been giving additional booster shots for months while leaders in the UK recently authorized them.

Campbell said early data from both Israel and the UK showed increased protections after a fourth dose (or a fifth for immunocompromised people).

(Read a summary about fourth doses in the New England Journal of Medicine.)

After BA.2, will we see additional variants that cause COVID-19?

Yes. New variants will develop after the BA.2 version spreads. But it’s unclear how concerning or how different the new variants will be.

“It’s unlikely that we’ll see as big a change as we did going from delta to omicron, but it’s very likely that we will see smaller changes,” Campbell said.

Unfortunately, as variants develop, they get better and better at spreading.

“The ‘desire,’ if you will, of a virus, is to spread more easily. And so, with each wave, we likely will continue to see incrementally more infectious variants,” Campbell said.

How do new COVID-19 variants develop?

It’s difficult to track exactly how viruses change in real time. But some variants develop in people who have suppressed immunities, such as a person who has advanced, untreated HIV or a person who is receiving bone marrow transplants, Campbell said.

Even with vaccines, people with suppressed immune systems can’t fight viruses well.

“They remain infected for very long periods of time and their immune responses are weak. So, they can’t completely shut down the virus. Their immunities may be strong enough, however, that they affect the virus. This allows the virus to change and adapt to immune responses,” Campbell said.

“Whether or not that’s how these new variants (like BA.2) have arisen is speculation,” Campbell said.

It’s impossible to know exactly where variants have sprung to life. Researchers can identify where variants were first detected.

“Omicron was first detected in southern Africa. Delta was first detected in India. Gamma was first detected in Brazil and mu in Colombia. We know that alpha was first detected in England and the (ancestral SARS-CoV-2) virus was detected in Wuhan, China,” he said.

“We can’t narrow it down to the first person who got a particular variant. These variants have emerged all over the world and in the U.S. as well,” Campbell said. “This is a global phenomenon.”

About the author

Katie Kerwin McCrimmon is a proud Coloradan. She attended Colorado College thanks to a merit scholarship from the Boettcher Foundation and worked as a park ranger in Rocky Mountain National Park during summers in college.

Katie is a dedicated storyteller who loves getting to know UCHealth patients and providers and sharing their inspiring stories.

Katie spent years working as an award-winning journalist at the Rocky Mountain News and at an online health policy news site before joining UCHealth in 2017.

Katie and her husband, Cyrus — a Pulitzer Prize-winning photographer — have three adult children and love spending time in the Colorado mountains and traveling around the world.