Moderna Says New Booster Performs Worse Against Surging COVID-19 Variant

A local resident receives the booster shot of the Moderna COVID-19 injection at a mass vaccination center operated by Japanese Self-Defense Force in Tokyo on Jan. 31, 202. Eugene Hoshiko/AP

Moderna’s updated COVID-19 vaccine booster performs worse against a virus variant that is becoming increasingly prevalent in the United States, the company announced on Nov. 14.

A clinical trial testing the updated booster, which U.S. regulators authorized in August without any clinical data, showed that it provides a higher level of neutralizing antibody titers than the old booster against the variant BA.5, according to Moderna.

BA.5 is currently the dominant strain in America, and antibody titers are believed to protect against COVID-19 infection and severe disease.

The results were based on 511 people, who received the new booster either 9 or 4 months after receiving an old booster.

But an analysis of approximately 40 participants using assays showed that that the titer levels triggered by the updated booster were 5-fold lower against BQ.1.1, the strain that is quickly becoming dominant in the United States, Moderna said in a press release.

The company said the level still signaled “robust neutralizing activity.”

The company still has not provided any data on clinical efficacy, or estimates of how protective the booster is against infection, severe disease, and/or death.

Its competitor, Pfizer, has also not provided any clinical efficacy data for its show, which the U.S. Food and Drug Administration gave emergency authorization to alongside Moderna’s on Aug. 31 based primarily on data from mice.

Pfizer said earlier in November that its updated booster triggered higher levels of neutralizing antibody titers against BA.4 and BA.5 than the old booster. It did not provide any antibody estimates against BQ.1.1.

According to variant proportions provided by the U.S. Centers for Disease Control and Prevention, BQ.1.1 and a similar variant, BQ.1, were responsible for about 13 percent of the cases in the United States in the week ending on Oct. 22, while BA.5 was behind a majority of the cases.

But the agency projects BQ.1 and BQ.1.1 becoming more dominant over time. In the week ending Nov. 12, the variants were behind 44 percent of cases, and BA.5 was responsible for 30 percent, according to the modeling.

All of the strains of subvariants of Omicron, which displaced Delta in late 2021.

BQ.1 is a sublineage of BA.5 that has some mutations in the spike protein, according to the World Health Organization (WHO). BQ.1.1, another sublineage, has an additional spike mutation.

BQ.1 is becoming increasingly prevalent in the United States and Europe “and therefore warrants close monitoring,” the United Nations group said, adding that “it is likely that these additional mutations have conferred an immune escape advantage over other circulating Omicron sublineages, and therefore a higher reinfection risk is a possibility that needs further investigation.”

There is no evidence thus far that BQ.1 increases disease severity, but protection by vaccines “may be reduced,” WHO said.

Some COVID-19 treatments that have proven effective against COVID-19 cases caused by BA.5 and some other subvariants are unlikely to work as well against BQ.1 and BQ.1.1, the National Institutes of Health COVID-19 Treatment Guidelines Panel said recently. That includes Evusheld, a monoclonal antibody combination.

“The thing that’s of concern to us, is that some of our tools in our armamentarium [sic] may be negated if in fact these newer variants become much more dominant than they are,” Dr. Anthony Fauci, the head of the National Institute of Allergy and Infectious Diseases, said in a recent radio interview.