Moderna: Redesign of vaccine slows variants

Moderna announced preliminary results Tuesday from its study of a COVID-19 vaccine intended to protect against variants, saying the findings show it can design a vaccine that offers better, longer-lasting protection than its initial product.

But the company said it was also testing another version of the vaccine that it expected would do even better, with results expected in late May or early June.

The company’s findings, published in a paper without being evaluated by outside scientists, offer hope that the nation will have a better vaccine by the fall, when COVID-19 is considered likely to reemerge in force.

Researchers at Moderna, other pharmaceutical companies and the National Institutes of Health have been racing to figure out how to redesign the existing vaccines in time for new booster doses to be manufactured over the summer. Moderna’s results are the first of their kind to be released.

The vaccines from Moderna and Pfizer-BioNTech continue to strongly protect most people from hospitalization and death caused by COVID-19. But their potency against infection wanes quickly. Federal officials recently authorized additional shots for people 50 and older, citing concerns about waning protection against severe disease in vulnerable populations.

Moderna said its research showed the promise of a so-called bivalent vaccine, even against other variants besides the two versions of the virus specifically targeted. In this case, researchers combined the existing vaccine with one designed to attack the beta variant, which was first detected in late 2020. They found the combination provided a stronger defense not only against those forms of the virus, but also against the delta and omicron variants, the company said.

Volunteers who got a booster shot of the reconfigured vaccine produced more than two times the level of antibodies against the omicron variant compared with those who got a booster dose of the existing Moderna vaccine. The added protection persisted for six months against the omicron variant but fell against delta to essentially the same level as that elicited by the existing vaccine, the study showed.

Moderna said although beta was an early variant, it was relevant to test because it contains several mutations that “have been persistent in more recent variants of concern, including omicron.”

Dr. Paul Burton, Moderna’s chief medical officer, said he was betting on even better results from combining the existing vaccine with one aimed at omicron. While the beta variant faded months ago, omicron is producing a stream of subvariants, including BA.1 and BA.2, and many experts suggest it is probably the best target for a new vaccine.

Given the ability of the omicron variant to evolve, Burton said, “I think we have to just assume it is going to be major player, still, in the fall.”