Omicron BQ variants dominate, XBB circulates at a low stage

A person receives a coronavirus disease (COVID-19) test as the Omicron variant coronavirus continues to spread in Manhattan, New York City, the United States, December 22, 2021.

Andrew Kelly | Reuters

The subvariants of the omicron BQ coronavirus have gained dominance in the United States as people gather and travel for Thanksgiving, putting those with compromised immune systems at increased risk.

BQ.1 and BQ.1.1 cause 57% of new infections in the United States, according to data released Friday by the Centers for Disease Control and Prevention. The once dominant subvariant omicron BA.5 now accounts for only a fifth of new Covid cases.

The BQ subvariants are more immune-avoidable and likely resistant to key antibody drugs like evusheld and bebtelovimab, which the National Institutes of Health says are used by people with compromised immune systems. These include organ transplant and cancer chemotherapy patients.

There is currently no substitute for these drugs. President Joe Biden, in an October speech, told people with compromised immune systems to consult with their doctors and take extra precautions this winter.

“New variants may render some existing protections for immunocompromised people ineffective. Unfortunately, that means you may be at particular risk this winter,” Biden said.

The sub-variant XBB is also currently circulating at a low level and causes around 3% of new infections. White House medical adviser Dr. Anthony Fauci, in a Tuesday briefing, said that XBB is even more immune-evading than the BQ subvariants.

Fauci, director of the National Institute of Allergy and Infectious Diseases, said the new boosters being developed against Omicron BA.5 may not be as effective against infections and mild illness caused by XBB. But the shots were intended to protect against serious illnesses, he said. Singapore has seen an increase in cases of XBB, but there hasn’t been a big increase in hospital admissions, he added.

Moderna and Pfizer said last week that their boosters induce an immune response against BQ.1.1, which is a BA.5 subvariant descendant.

Fauci said in the press conference that public health officials believe there is enough immunity to vaccination, booster and infection to prevent a repeat of the unprecedented Covid surge that occurred last winter when Omicron first arrived.