MINNESOTA – The ever-changing coronavirus has spawned another super-infectious version of Omicron that worries scientists as it spreads across India and appears in many other countries, including the United States.
Scientists say the subvariant, called BA.2.75, could spread rapidly and evade immunity from previous vaccinations and infections. It is unclear whether it could cause more severe disease than other Omicron subvariants, such as BA.5, which are prevalent worldwide.
“It’s too early for us to draw too many conclusions,” said Matthew Binnicker, director of clinical virology at the Mayo Clinic in Rochester, Minnesota. “But it does seem that, especially in India, transmission rates show that kind of exponential increase.” Whether it will override BA.5 is yet to be determined, he noted.
Still, the fact that it has already been detected in many parts of the world with lower levels of viral surveillance “is a preliminary indication that it is spreading,” said Shishi Luo, head of infectious diseases at Helix, a company that offers viral sequencing information to the US Centers for Disease Control and Prevention (CDC).
The new subvariant has been detected in distant states in India and appears to be spreading faster than other variants there, said Lipi Thukral, a scientist at the Scientific and Industrial Research Council-Institute of Genetic and Integrative Biology in New Delhi. It has also been identified in about 10 other countries, including Australia, Germany, Great Britain, and Canada. Two cases were recently detected on the West Coast of the United States, and Helix identified a third case in the United States last week.
Adding to the concerns of experts is the large number of mutations that distinguish this new sub-variant from previous versions of Omicron. Some of these mutations are related to the spinal protein and could make the virus attach to cells more efficiently, Binnicker said.
Omicron BA.2, also known as “Stealthy Omicron”, has been the dominant variant of COVID-19 in the United States since March 2022.
Another concern is that the genetic changes may make it easier for the virus to evade old antibodies, protective proteins the body produces in response to previous vaccines or sub-variant infections.
However, experts say vaccines and booster doses remain the best defense against severe COVID-19. The United States is likely to have vaccine formulations adjusted to recent Omicron strains in the fall.
“Some might say, ‘Well, vaccinations and boosters haven’t stopped people from getting it.’ And yes, that is true,” she explained. “But what we have seen is that the rates of people ending up in hospital and dying have dropped significantly. As more people get vaccinated, boosted or naturally infected, we start to see underlying levels of immunity rise around the world.”
It could be several weeks before we get an idea of whether the new subvariant could affect the trajectory of the pandemic. Meanwhile, Dr. Gagandeep Kang, who studies viruses at Christian Medical College in Vellore, India, said growing concern about the subvariant underscores the need for more sustained efforts to detect and track viruses, combining genetic efforts with information from the real world about who gets sick and how seriously. “It’s important that surveillance is not an intermittent strategy,” he said.
Luo said BA.2.75 is another reminder that the coronavirus is constantly evolving, and spreading.
“We would like to go back to pre-pandemic life, but we still have to be careful,” he said. “We must accept that we now live with a higher level of risk than before.”
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