Moderna said Tuesday that its modified Covid-19 booster shot, designed to target two strains of the coronavirus, generated a strong immune response against multiple variants of concern, including omicron.
The drugmaker's redesigned booster — a so-called bivalent vaccine —combines a beta variant-specific vaccine with the company’s original formula into a single shot. The redesigned booster did not, however, include an omicron-specific target.
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The company said the modified shot appeared to offer even stronger protection against the virus than its existing booster, which is still formulated to target the original form of the coronavirus identified in late 2019.
The findings were announced in a company press release, so the full data hasn’t yet been reviewed by outside scientists.
Dr. Isaac Bogoch, an infectious diseases physician and associate professor of medicine at the University of Toronto, called Tuesday’s results “helpful,” but added that more data is needed before scientists consider whether to move forward on the vaccines.
Moderna has been testing modified booster shots that could be distributed across the country this fall, when immunity from previous shots will likely begin to wane and Covid-19 cases are expected to rise.
Among the other candidates Moderna is testing is another bivalent vaccine that combines an omicron-specific vaccine with its original vaccine.
The omicron variant dealt a significant blow to the protection provided by the existing booster shots from both Moderna and Pfizer-BioNTech.
Early data from the omicron bivalent vaccine, which Moderna has called its “lead candidate” for the fall, is expected later in the second quarter, the company said.
Tuesday’s results on the beta-variant bivalent vaccine offers hints that the omicron bivalent vaccine will also work well, the company said, because the beta variant has some mutations also seen in the omicron variant.
The redesigned shot was tested in a clinical trial of 300 people at 50 micrograms — the same dosage currently given in the existing booster shot. (The first two doses of the Moderna vaccine, called the primary series, are 100 micrograms each.)
The shot was also well tolerated, the company said, producing side effects in trial participants similar to those seen in its existing product.
Moderna did not say whether they would be submitting the beta-variant bivalent vaccine results to the Food and Drug Administration. The modified booster is currently not available.
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