An Omicron subvariant known as BA.2 is expected to become dominant in the U.S. in the coming weeks.

BA.2 is at least 30% more transmissible than its cousin BA.1, and it has been driving new COVID-19 surges in the United Kingdom and other European countries. According to a World Health Organization report, the highly contagious subvariant is dominating cases worldwide, and accounted for about 86% of cases reported to the WHO between Feb. 16 and March 17.

In Hong Kong, BA.2 recently brought on a deadly outbreak reminiscent of the early days of the pandemic.

Across the European Union, new daily cases are up more than 70% since the beginning of March. Hospitalizations in the U.K. have been going up as well.

A patient outside the Accident and Emergency Ward of the United Christian Hospital in Hong Kong on March 4. (Marc Fernandes/NurPhoto via Getty Images)

So far, in the United States, BA.2 accounts for 35% of new coronavirus cases, according to the Centers for Disease Control and Prevention. U.S. health officials expect the strain to outcompete the other variants and to become dominant soon. However, there are some reassuring signs that BA.2 might not hit the United States as hard as Europe, and health experts in the U.S. don’t foresee a major surge in cases from the Omicron subvariant.

“We’ll likely see an uptick in cases, as we’ve seen in European countries, particularly the U.K.,” White House chief medical adviser Dr. Anthony Fauci told ABC’s “This Week.” “Hopefully, we won’t see a surge — I don’t think we will.”

While BA.2 appears to be more transmissible than BA.1 and is gaining ground in the U.S., it has not interrupted the country’s downward trend in COVID-19 cases and hospitalizations.

“So right now in the United States, case rates are still falling, despite an increased predominance of BA.2 compared to BA.1,” said Dr. Lucy McBride, a Yahoo News medical contributor. “Because of widespread vaccinations and because people do have some immunity from past infections … we are seeing fewer deaths, hospitalizations, and overall we’re doing much better than we were even a month ago.”

Dr. Anthony Fauci speaks in front of a White House seal.

Dr. Anthony Fauci discusses the Omicron variant at a White House press briefing on Dec. 1. (Kevin Lamarque/Reuters)

There are no indications so far that BA.2 causes more severe disease overall than its predecessor, Delta. Another plus, McBride said, is that the vaccines available have continued to do an excellent job of protecting against severe disease and death.

“Right now, it’s very important to get vaccinated, particularly if you have not been vaccinated. We all will be exposed at some point to the coronavirus, whether it’s this variant or the next one, and you’d rather be armed with antibodies and immunity from having been vaccinated,” McBride said.

People who are eligible for a booster shot, particularly the elderly or those at high risk because of underlying health conditions, should consider getting the additional dose, because it provides much more protection against Omicron than just two doses.

A sign for a COVID-19 vaccination center in London, with an arrow and the words: This Way.

A sign for a COVID-19 vaccination center in London on Jan. 28. (Ray Tang/Xinhua via Getty Images)

McBride’s argument is supported by recent U.K. data showing that booster protection against symptomatic COVID-19 infection was 70% for BA.2 and 63% for BA.1. Protection against death caused by an Omicron infection was 95% in people who had received boosters and who were age 50 and older, the same research showed.

But what if you have already been infected with Omicron BA.1? Some recent research has shown that previous infection with the BA.1 version of the Omicron coronavirus variant provides strong protection against its relative, BA.2. However, McBride says it is worth talking to your primary care provider about getting the full vaccine series, based on your age, your underlying health conditions, your occupation and your immune status.

“Once you’ve been vaccinated, you’ve taken the claws and the fangs away from the virus. You’ve turned it into a more manageable illness, and the chance of getting severely ill and the chance of getting long-term consequences, while they’re not zero, they’re dramatically reduced,” she said.