Since the pandemic began more than two years ago, sudden increases in COVID-19 cases have been fueled by the emergence of new variants, including delta and omicron. Currently, a more infectious omicron subvariant, called BA.5, accounts for most new US cases, but a separate, newer subvariant is attracting attention.
Known as BA.2.75, the subvariant may be able to evade immunity to vaccines and previous infection, researchers claim. The strain includes several mutations in the gene that codes for the spike protein of the virus, which allows the virus to bind to the host cell receptor more efficiently, Dr. Matthew Binnicker, director of the Clinical Virology Laboratory at the Mayo Clinic, explained in an article.
Discovered in India in May, the strain appears to be spreading faster than other subvariants there, and is under surveillance by both the World Health Organization and the Centers for Disease Control and Prevention. Cases have emerged in at least a dozen countries, including the United States, where numbers remain extremely low.
A total of 13 cases have been confirmed in the United States, with three of them in Illinois, said Dr. Allison Arwady, commissioner of the Chicago Department of Public Health.
At this point, it does not appear that the strain will lead to another major wave of COVID in the US, but the possibility remains.
“…We’re keeping an eye on it,” Arwady said. “We’re doing a good job of testing and we’re excited here, which is one of the reasons we can find it [BA.2.75].”
BA.2.75 spreads more efficiently from person to person, according to Binnicker, who explained that there is no solid data showing that it causes more severe disease compared to other subvariants. But as more people become infected, the chances of the virus infecting someone who is more vulnerable increases.
“…Those who have an immunocompromised condition can still end up with serious illness and be hospitalized,” he explained. who are highly exposed to worse outcomes, then increases.”
The threat from the BA.2.75 variant in India underscores the importance of global vaccination, Dr. Sabrina Assoumou, a physician at Boston Medical Center, told NBC Boston.
“We’re not going to get through this pandemic if we don’t make sure that everyone, everywhere, is safe,” she said.
India’s population has a different immunity than the United States, several Boston doctors said, because different vaccines were given at different times and different variants circulated at different times. These variables result in fluctuating levels of infection-induced immunity.
“We can’t assume that what happens there will happen here, and yet we have to prepare for surges. We’re always now preparing for surges,” said Dr. Shira Doron of Tufts Medical Center. “Variants will emerge that evade immunity from the vaccine and previous infection, and we can never really know exactly what they’re going to do to our case rates until we get there.”
As the school year approaches and new variants, including BA.2.75, lead to more cases, monitoring the number of infections will be critical.
“There is definitely concern that as we go into the fall and winter months of 2022, and then into 2023, that the new strains of the virus, including BA.27.5, will increase as kids go back to school,” Binnicker said. “They are going to interact and that will increase the speed of transmission of viruses, including COVID 19.”