When the FDA advised vaccine-makers in late June to engineer their boosters to target subvariants BA.4 and BA.5, at the time the "sister variants" accounted for a slight majority of infections. Four months later, new mutations BQ.1 and BQ.1.1 have surpassed the subvariants the omicron boosters targeted.
As of Nov. 18, BQ.1 and BQ.1.1 account for 49.7 percent of infections, and the CDC currently is tracking 12 other omicron subvariants.
Here is what experts are saying about how new variants are affecting COVID-19 vaccines:
- Moderna's bivalent omicron booster: When tested against BQ.1.1, the new booster showed "robust neutralizing activity."
Follow-up tests of Moderna's omicron-targeting booster found higher neutralizing antibody responses against BA.4, BA.5, BA.2.75 and BA.1, the company said in an Oct. 19 news release. The consistent results indicate the booster "elicits broad cross-neutralization against omicron variants," Moderna said.
- Pfizer's bivalent omicron booster: Compared to its original formula, neutralizing antibodies against BQ.1.1 increased 8.7 times in Pfizer's omicron-focused booster, the company said Nov. 18. The tweaked vaccine also offers better protection against omicron subvariants BA.4.6, BA.2.75.2 and XBB.1.
"Our latest research of the adapted-vaccine shows a better immune response against the variant and may potentially provide broader protection against future variants," a spokesperson told Becker's in mid-October.
Here is what experts know about the efficacy of FDA-approved COVID-19 treatments:
- Pfizer's antiviral treatment, Paxlovid: The drug does not bind to the spike protein like other treatments; rather, it binds to SARS coronavirus' main proteinase "to inhibit viral replication," a spokesperson said.
Because of this distinction, Paxlovid has avoided resistance from current variants of concern, the spokesperson added.
- Merck's Lagevrio: Recent studies are hinting that Merck's antiviral is waning in efficacy. A trial sponsored by the University of Oxford found that the drug failed to reduce hospitalizations and deaths of the 25,000 people involved in the study. A Merck spokesperson said the trial also found Lagevrio reduced symptoms, time to recovery and doctor visits.
Another recent study found Lagevrio reduced hospitalizations and deaths among patients 65 and older but not for younger age groups.
- AstraZeneca's Evusheld: New viral variants may be resistant to Evusheld, the only COVID-19 preexposure prophylaxis treatment with emergency use authorization, the FDA said Oct. 3. The agency still recommends Evusheld as a preventive measure for people at the highest risk of severe illness who cannot get vaccinated.
"COVID-19 remains a significant health concern for the immunocompromised who face a high risk for severe COVID, hospitalization and death if they get infected (about 2 percent of the global population)," an AstraZeneca spokesperson said.
The drugmaker said it is continually working with health authorities on "variant evolution."
- Eli Lilly's bebtelovimab: The FDA updated its healthcare provider fact sheet for the COVID-19 treatment Nov. 3 with the warning that bebtelovimab is unlikely to neutralize omicron subvariants BQ.1 and BQ.1.1.
The drug, which Eli Lilly began selling commercially in August, remains authorized, according to the FDA.
In late October, a spokesperson did not specify whether BQ.1 was a concern but said "bebtelovimab is currently the only available monoclonal antibody with neutralizing activity against the omicron variant and subvariant BA 4.6."