The trial is one of the first to examine whether Omicron-specific immunizations may offer better protection against the strain currently driving outbreaks worldwide. With the virus mutating rapidly, medical experts are trying to decide when and how to modify vaccines to best thwart existing and future variants. Unlike with influenza, there’s no established system yet in place to determine how often COVID vaccines should be updated or administered. 

Moderna plans to submit the data to drug regulators in the coming weeks, the Cambridge, Massachusetts-based company said in a statement. The magnitude of the antibody increases produced by the booster suggests that COVID shots would not have to be given more than once a year, Moderna Chief Medical Officer Paul Burton said. 

“It is not a borderline result, it is really very robust,” he said in an interview. “We know that level will decay over time, but being able to boost it up that high is really remarkable.”

Moderna shares rose 2.9% as of 9:35 a.m. Wednesday in New York. They’ve lost about two-thirds of their value since peaking at $484.47 in August, as concern about the pandemic eases.

What Bloomberg Intelligence says:

“Yes, Moderna’s new bivalent shot induced more neutralizing antibodies against Omicron than its marketed Spikevax, but the differential may not be big enough to improve efficacy—or sales. Regulators will probably approve the shot, given the higher antibody levels, yet actual use depends on efficacy against the omicron variants now circulating, which could turn out to be low.”

—Sam Fazeli, BI senior pharmaceuticals industry analyst. Click here to read the research. 

The company is already manufacturing the shot that combines components from its original immunization with updated elements aimed at Omicron, and plans to switch most of its production to the so-called bivalent vaccine, Burton said. Hundreds of millions of doses should be available by the fall, he said. The shot will be ready to ship as soon as August, CEO Stephane Bancel said on a call with analysts.  

Study results

In the trial, 437 people got a booster shot of the bivalent vaccine, and those who weren’t infected at the start had antibody levels against Omicron one month later that were 8-fold higher than their baseline levels, Moderna said. They had a superior neutralizing antibody response against Omicron compared with 377 people who were given the company’s existing booster, without sacrificing their response to the original strain, the company said. 

The new bivalent booster also significantly bolstered antibodies in people who had been previously infected, Moderna officials said on the call. Also, while the immune response produced by the bivalent vaccine hasn’t yet been evaluated against newer versions of Omicron that are now circulating, company executives said that high level of antibodies produced against the original Omicron should be enough to provide a protective margin, they said.

“We think we are still going to be in a very comfortable place,” Moderna president Stephen Hoge said on the call.

Side effects were similar to the existing shot, Moderna said. All 814 trial participants had previously received three doses of the vaccine.

The study “met all pre-specified endpoints,” the company said.

Pfizer Inc. and BioNTech SE are also testing Omicron-specific booster shots and are expected to have data in the coming weeks. 

On June 28, medical advisers to the Food and Drug Administration will meet to discuss whether future COVID vaccines should be modified to account for ever-changing variants, and, if so, which strain or strains should be put into booster shots for the fall.