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Moderna's omicron booster won't be ready before summer

The company started clinical trials on the variant-specific vaccine this week.
Image: A healthcare worker administers a dose of the Moderna Covid-19 vaccine in Gilroy, Calif., on March 4, 2021.
A health care worker administers a dose of the Moderna Covid-19 vaccine in Gilroy, Calif., on March 4, 2021. Nic Coury / Bloomberg via Getty Images file

Moderna plans to seek authorization from the Food and Drug Administration for its omicron-specific Covid-19 vaccine booster by the summer, the company’s chief medical officer said Thursday — a time frame that means that the targeted vaccine may not be available to the public until the second half of the year.

Dr. Paul Burton, Moderna’s chief medical officer, told NBC News that the company is thinking ahead to the second half of 2022 when omicron may still be circulating widely.

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Published data shows the booster dose of Moderna’s original vaccine still provides strong protection against certain variants of the coronavirus, like delta. But, Burton said, there’s “a bit less” against the extremely contagious omicron variant after six months.

“We’re going to do the work now,” he said, referring to the omicron-specific vaccine. “We’re going to generate it, we’re going to produce it. We would be certain that we would be filing it, some different version of it, by the summer.”

Moderna announced Wednesday that it had started clinical trials for the omicron-specific booster.

Pfizer and BioNTech are also testing their version of an omicron-specific vaccine, which could be ready to launch as early as March.

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One of the benefits of mRNA vaccines that sets them apart from others is how quickly they can be made, though scientists still must take time to demonstrate that the shots actually work and prepare data to be scrutinized by federal regulators.

Some health experts have questioned whether omicron-specific shots will even be necessary by the second half of the year, or if it will be too late, especially because omicron-fueled cases have begun to decline in the United States and it’s always possible that a new and more virulent variant could emerge. There’s also a push for next-generation Covid vaccines to be multivalent, meaning they would protect against several variants at once.

Scientists have already detected a subvariant of omicron, known as BA.2, though experts say it’s still unknown whether it is more contagious or causes more severe disease.

Dr. Jesse Goodman, an infectious disease specialist at Georgetown University Medical Center and a former chief scientist with the FDA, said it’s still important to have an omicron-specific vaccine available because another dangerous variant could emerge that is more closely related to omicron than it is to prior strains.

The existing vaccines still target the original strain first identified in late 2019.

Goodman also said that Moderna and Pfizer’s trials could answer questions, including whether an omicron-specific vaccine, or future vaccines like it, can generate “broadly” reactive antibodies that can also target earlier strains like delta and beta.

Or, “it could be that it never gets used,” he said. 

Covid vaccines in development for the antibody-evading beta variant, for example, were later found to be unnecessary after that variant didn’t gain a foothold and spread widely across the globe.

Dr. Anna Durbin, a vaccine researcher at Johns Hopkins University agreed that Moderna should still pursue the modified vaccine, adding the process for selecting the right Covid booster could become similar to the one for the annual flu shot.

Scientists constantly monitor influenza strains and, each year, select three to four that they think will be circulating widely to include in the flu vaccine.

Burton said Thursday the company will test a 50 microgram dose of the omicron-specific vaccine, the same dosage given in the existing booster shot, as well as a 100 microgram dose, the same dosage given in the first two shots of the primary series.

He said it’ll take a couple more months before the modified vaccine has been adequately tested in people and the company can analyze the blood samples. The final decision to seek the FDA’s OK will be guided by science and discussions with federal regulators, he added.

He said the company is also pursuing vaccines that can target multiple variants at once or multiple viruses, like both the coronavirus and influenza, in a single shot.

Moderna could begin testing its combined shot for Covid and the flu late this year and it could be ready to launch in late 2023, he said.

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