Moderna announced Monday that a booster shot of its COVID-19 vaccine significantly increases antibody levels against the highly-transmissible Omicron variant.
A 50 microgram jab — the authorized dose for a third shot — saw a 37-fold increase in neutralizing antibodies, the vaccine maker said.
Moderna also tested a 100 microgram booster dose, which increased antibody levels 83-fold. The first two shots of Moderna’s vaccine are both 100 micrograms.
The company said the higher booster dose was generally safe and well-tolerated, although there was a trend toward slightly more frequent adverse reactions.
Moderna CEO Stephane Bancel called the data “reassuring” but said it will continue to “rapidly advance an omicron-specific booster candidate into clinical testing in case it becomes necessary in the future.”
However, for now, the drugmaker said the current version of its vaccine – mRNA-1273 — will continue to be its “first line of defense against Omicron.”
“What we have available right now is 1273,” Dr. Paul Burton, Moderna’s chief medical officer, told Reuters.
“It’s highly effective, and it’s extremely safe. I think it will protect people through the coming holiday period and through these winter months, when we’re going to see the most severe pressure of Omicron,” he added.
The data, which has not yet been peer-reviewed, tested blood from 20 booster recipients with each dose against a pseudovirus engineered to resemble the Omicron variant, the company said.
Antibody levels were measured on day 29 post-boost.
Burton said it would be up to governments and regulators to assess whether they want the enhanced level of protection that a 100 microgram dose might provide.
US regulators authorized Moderna’s 50 microgram booster in October.