The subvariants, which have been shown to pose challenges to vaccines and treatments, are raising concerns about a potential winter wave of COVID-19.
The omicron subvariants that present “serious threats” to COVID-19 vaccines are growing in the U.S., according to data from the Centers for Disease Control and Prevention.
BQ.1.1, BQ.1 and XBB were responsible for more than 76% of coronavirus infections this week, according to CDC estimates – up from nearly 71% of cases last week.
The subvariants are raising concerns about a potential winter wave of COVID-19 as they are posing challenges to vaccines and monoclonal antibody treatments.
A study published this week found that the subvariants are the “most resistant SARS-CoV-2 variants to date.”
“Together, our findings indicate that BQ and XBB subvariants present serious threats to current COVID-19 vaccines, render inactive all authorized antibodies, and may have gained dominance in the population because of their advantage in evading antibodies,” the authors wrote.
The authors did note, however, that the updated COVID-19 shots performed slightly better than the original shots against the new subvariants and emphasized that COVID-19 vaccines are still effective at preventing hospitalizations and severe disease.
Data published by the CDC on Friday quantified that protection, finding that the new shots, which are designed to take on BA.4 and BA.5 as well as the original coronavirus strain, may reduce the risk of severe COVID-19 by 50% or more.
The data was particularly good news for seniors. It found that the shots were 84% effective at preventing people aged 65 and older from being hospitalized with COVID-19 compared to the unvaccinated.
But uptake of the booster remains quite low, with only about 14% of the entire eligible population and nearly 36% of eligible people aged 65 and older getting the shot.
The studies come as U.S. officials renew warnings over increasing coronavirus cases, with the Biden administration this week restarting its free at-home COVID-19 test program for a limited time.
“As expected, we’re seeing COVID rising across the country this winter,” White House COVID-19 response coordinator Ashish Jha said at a press briefing on Thursday. “And while COVID isn’t the disruptive force it once was, we are focused on ensuring that the U.S. is prepared for this winter no matter what the virus throws at us.”
The vast majority of U.S. counties – nearly 75% – are experiencing a “high” level of COVID-19 transmission, according to CDC data.