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- Recent research finds the current dominant strain, called BA.2 or the “stealth” Omicron subvariant, could evade natural and vaccine-induced immunity.
- Cases are rising in multiple countries, including those that had previously evaded some of the worst COVID-19 waves during the pandemic.
- Experts say this subvariant may be more able to spread widely, but people should not be overly concerned if they are vaccinated against COVID-19.
As the BA.2 subvariant of Omicron spreads, countries that have evaded some of the worst of the pandemic are seeing COVID-19 cases rise.
China reported its first COVID-19-related deaths in almost a year on March 19, and data from the World Health Organization (WHO) shows Germany recorded more than 1,300 deaths in the past week.
“We are in a situation that I would like to describe as critical,” German Health Minister Karl Lauterbach, ScD, said at a weekly coronavirus press briefing on March 11, reported state-owned broadcaster, DW.
“We have strongly rising case figures again,” Lauterbach warned. “I keep reading that the Omicron variant is a milder variant but that’s only true to a limited extent.”
Recent research finds the current dominant strain, called BA.2, or the “stealth” Omicron subvariant, could evade natural and vaccine-induced immunity and carry a significant risk of reinfection.
Does this mean we’re facing a surge similar to what happened at the start of the pandemic?
BA.2 is a variant of concern
“BA.2, like BA.1, is a subvariant of Omicron, so it falls under the umbrella of variants of concern,” Dr. Steven Phillips, an expert on zoonotic infections and who practices in Connecticut, told Healthline.
He explained that BA.2 has “extensive” genetic mutations and is about 40 percent more transmissible than BA.1.
“They’re sometimes calling BA.2 ‘stealth’ Omicron because its genetic mutations make it harder to differentiate from Delta by PCR testing,” Philips said.
Phillips said BA.2 is similar to prior coronavirus variants, and infection can bring upper respiratory symptoms, body aches, and flu-like symptoms.
Phillips also noted animal data showing BA.2 could be more severe than BA.1 in hamsters without acquired immunity to other variants, whether by vaccine or acquired naturally.
“When it’s a serious case, we still can have similar clotting problems and cytokine storm which can be dangerous,” he said. “Thankfully, both subvariants of Omicron are less virulent than Delta.”
Reinfection with BA.2 has happened after BA.1 infection
Danish researchers discovered that infection with two different Omicron subtypes is possible.
For the study, they selected a subset of samples from almost 2 million cases in Denmark from Nov. 22, 2021, until Feb. 11, 2022.
“From a total of 187 reinfection cases, we identified 47 instances of BA.2 reinfections shortly after a BA.1 infection,” study authors wrote.
They emphasized that reinfection was relatively rare in Denmark, and mostly affected younger, unvaccinated people.
BA.2 evades vaccine protection better than BA.1
Another recent study, not yet peer reviewed, finds BA.2 more easily evades vaccine protections than BA.1.
However, these researchers also found that vaccinated people with a breakthrough infection don’t transmit the virus as easily as unvaccinated people.
This might be because vaccinated people have a lower viral load than unvaccinated people, so vaccination still slows disease spread.
Signs point toward an increase in cases
There are signs that cases may soon start to increase in the United States.
Data from the Centers for Disease Control and Prevention (CDC) shows COVID-19 has been detected in increasing amounts in wastewater in certain areas.
“Wastewater analysis is showing that there is a thousand times more virions (whole virus) in the wastewater than before,” said Dr. Robert G. Lahita, director of the Institute for Autoimmune and Rheumatic Diseases at Saint Joseph Health.
Lahita confirmed this usually precedes a rise in COVID-19 cases.
He added that since most people are self-testing at home, there is no way to know who or how many people have had an infection, unless they go to a hospital or emergency room.
Lahita believes said people should not panic about the potential for the BA.2 subvariant to lead to a rise in cases.
He pointed out that it does not appear to cause more severe symptoms than earlier variants of the coronavirus. Additionally, many more people have either been vaccinated or have developed COVID-19 in the past, providing protection against severe disease in the future.
Even if people without immunity to BA.1 or BA.2 end up developing COVID-19, he added they likely will experience an upper respiratory infection rather than infection deep in the lungs.
“I spoke with a woman last night who was in bed aching all over, and she was totally congested and could barely talk, but she’s at home and she’s not in the hospital, she’s not short of breath,” he said.
However, Lahita doesn’t believe we’re finished with the pandemic — or that it’s time to give up masking.
“It’s too early to throw the masks away, because you never know,” he cautioned. “There could always be the development of a new, highly effective, and clinically dangerous variant like the Delta variant.”
Nevertheless, Lahita insisted that mass herd immunity means even a variant like Delta shouldn’t be as concerning as during the beginning of the pandemic.
But Phillips cautions not to forgo all protective measures just yet.
“I think that we have to continue to be vigilant and not let ourselves get overconfident,” said Phillips. “Yet we have to find a balance where life can go on.”
The bottom line
New research finds that the “stealth” Omicron subvariant, BA.2, has greater ability to evade immune protections and increased risk of reinfection.
Experts say BA.2 has extensive mutations and is about 40 percent more infectious than the original Omicron variant.
They also say that Omicron symptoms are typically mild, and herd immunity is at a level where it may not have the severe impact seen with earlier variants.