Moderna Booster Increases Protection Against Omicron, Company Says

Brenda Goodman

December 20, 2021

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Moderna on Monday announced that a booster dose of its COVID-19 vaccine increased levels of antibodies that fight the Omicron variant.

The 50-μg dose of its mRNA vaccine — which is half the dose given for first-round vaccinations — increased levels of antibodies to fight Omicron by 3700% in people studied within 1 month of getting their third shots, the company said in a news release.

What's more, a 100-μg booster, the dose that's given in the primary series, increased antibody levels 8300% after a third dose. Moderna is still studying its 100-μg dose as a booster, but in clinical trials, the company says a third 100-μg dose appears to be generally safe.

The studies were small, including just 20 healthy people in each group. Before they got their third shots, researchers drew their blood and measured levels of proteins called neutralizing antibodies, which are one of the body's first lines of defense against invaders. Levels of the specific kinds of antibodies that are able to disable Omicron were low, the company said.

But that changed 1 month after people in the study were given a third dose as a booster. When scientists drew their blood and tested it in a lab against key pieces of the Omicron variant, levels of these antibodies had increased substantially.

"The dramatic increase in COVID-19 cases from the Omicron variant is concerning to all. However, these data showing that the currently authorized Moderna COVID-19 booster can boost neutralizing antibody levels 37-fold higher than pre-boost levels are reassuring," Stéphane Bancel, chief executive officer of Moderna, said in a statement.

The company said it would continue to advance the production of next-generation vaccines specifically designed to fight variants like Delta and Omicron, but in the meantime, getting the currently available shots would help.

The news comes after Pfizer reported last week that a third dose of its COVID-19 vaccine increased levels of neutralizing antibodies against Omicron by 25 times, enough to bring protection back to the level most people had soon after their first two shots.

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