BA.2, also called “stealth omicron,” is no longer the only subvariant or type of omicron scientists are watching. BA.2.12.1, another sublineage of omicron, is a newer version that’s increasing in some parts of the US. It may also be more transmissible and capable of infecting more people than BA.2, which was already more contagious than BA.1 — the “original” omicron, which caused the winter wave.
But that’s to be expected, according to the US Centers for Disease Control and Prevention.
“As the virus continues to evolve, we expect to see new variants (and their many different lineages and sublineages) emerge and disappear as they compete against each other and other circulating viruses,” the CDC said in an April 22 summary.
Though COVID-19 cases are rising again in the US after a sharp fall from the winter surge, the daily number of deaths from the virus are still declining. Hospitalizations are experiencing a small increase. Close to 1 million people in the US have died from COVID-19.
A new report from the CDC released Tuesday confirmed that nearly 60% of Americans, and as many as 75% of children, have had COVID-19 as of February 2022. Researchers looked at infection-induced antibodies, which are different from vaccine-induced antibodies, Dr. Kristie Clarke, a researcher on the study, noted in a media briefing Tuesday. She also said prior infection doesn’t necessarily mean immunity from COVID-19, as researchers didn’t measure the level of protective antibodies against COVID-19 reinfection or severe disease.
Here’s what to know about BA.2 and the other versions of omicron.
What are subvariants or sublineages?
Variants are made up of multiple lineages and sublineages. Each variant has a “parent” lineage, according to the CDC, followed by other lineages, which you can think of like a family tree. As the virus spreads between people, mutations occur, but not all of them change the characteristics of the virus in meaningful ways.
The omicron variant and its sublineages made the virus much more contagious and capable of infecting more people, but it’s lead to less severe disease, on average, than the delta variant.
Genomic surveillance can detect variants and sublineages. Scientists in South Africa were able to quickly identify omicron as a new variant this winter because of the way it presents through PCR tests. The original omicron causes a dropped signal or marker on the test that sets it apart from delta, which was the dominant variant prior to omicron. BA.2, however, doesn’t have the same signal, called an S gene target failure. This makes it more stealthy, though genomic sequencing (which happens to about 10% of COVID-19 PCR tests in the US) will detect all omicron subvariants and coronavirus variants in general.
What are the symptoms of omicron’s subvariants?
Data available currently suggests that BA.2 doesn’t cause more severe disease than the original omicron variant, even if it is more transmissible. (The WHO notes that the transmission difference between original omicron and stealth omicron is smaller than the difference between delta and omicron.)
There isn’t research available right now to suggest BA.2 causes different symptoms than the original omicron variant. For many people who catch COVID-19 (especially those who are fully vaccinated or boosted), COVID-19 symptoms resemble cold symptoms such as sore throat and runny nose and you should stay home if you’re sick.
Read more: Is It Allergies or COVID? How to Tell the Difference
Is BA.2.12.1 more severe? Will the vaccines work?
The WHO, considering all available real-world data, concluded there’s no reported difference in severity between omicron BA.1 and BA.2, despite the latter’s growth advantage.
Between BA.2 and BA.2.12.1, the newer version is believed to be about 25% more transmissible, Walensky said Tuesday at a media briefing, but more evaluation and research is underway.
Like the original omicron, BA.2 means more fully vaccinated people will experience breakthrough infections. But those who are fully vaccinated, and especially boosted against COVID-19, “continue to have strong protection against severe disease,” Walensky said at the briefing.
In a March 8 statement, the WHO said that though there are cases of people getting sick with BA.2 after they’ve already had COVID-19 caused by omicron, early data suggests that infection with BA.1 provides “substantial protection” against BA.2, at least for a while.
The information contained in this article is for educational and informational purposes only and is not intended as health or medical advice. Always consult a physician or other qualified health provider regarding any questions you may have about a medical condition or health objectives.
