Moderna says its new 'bivalent' vaccine shows promise against COVID variants

A health care worker prepares the current COVID vaccine booster shots. A vaccine that combines the original strain with the omicron strain is the lead candidate for a fall campaign.

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Moderna announced Tuesday that a new version of the company's COVID-19 vaccine appears to provide stronger, longer- lasting protection against variant of the virus than the original vaccine.

Preliminary results from a study show that a vaccine that targets both the original strain of the virus and the variant that is related to the flu can produce high levels of antibodies for months.

"We believe that these results confirm our bivalent strategy," said Bancel in the news release.

Bancel said that another bivalent vaccine that combines the original strain with the omicron strain is the lead candidate for a fall vaccine campaign. Results from the testing of that version are expected later this spring, according to Moderna.

Bancel said that a bivalent booster vaccine would create a new tool as we respond to emerging variant.

The study has not yet been reviewed by independent scientists.

Nathaniel Landau, a microbiologist at New York University, wrote to NPR that the paper is a proof of principle that supports the idea of a bivalent vaccine. The most useful version would probably be an omicron-specific one.

The results are encouraging according to Dr. Jesse Goodman, a former top Food and Drug Administration scientist. Additional research is needed to confirm the approach.

Other things could be at play in making the bivalent booster look better.

The results are "unimpressive" according to John Moore, an immunologist at Weil Cornell Medicine.

Dr. Gounder said the company's announcement seemed misleading because it compared the antibodies from just two doses of the original vaccine with a third dose of the new vaccine.

Researchers are testing several new versions of Moderna's and Pfizer's vaccines to see if they give the same protection as the omicron variant. Federal officials are hoping to see enough results by later this spring to give companies enough time to produce enough vaccines for another round of shots in the fall, when infections from previous vaccinations may be waning and another surge could be looming.