Moderna says redesigned vaccines can better protect against Covid-19 variants

NEW YORK • Moderna announced preliminary results on Tuesday from its study of a coronavirus 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 late next month or early June.

The company's findings, published in a paper without being evaluated by outside scientists, offer hope that the United States will have a better vaccine by autumn, when the coronavirus is considered likely to re-emerge in force.

Researchers at Moderna, other pharmaceutical companies and the National Institutes of Health have been racing to figure out how to redesign 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 hospitalisation and death caused by Covid-19. But their potency against infection wanes quickly.

Federal officials recently authorised additional shots for people aged 50 and older, citing concerns over waning protection against severe disease in the elderly and those with underlying medical conditions. 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 defence 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 that while Beta was an early variant, it was relevant to test because it contained several mutations that "have been persistent in more recent variants of concern, including Omicron".

Moderna chief medical officer Paul Burton said he was betting on even better results from combining the existing vaccine with one aimed at Omicron.

NYTIMES