FDA Considers Lower Dosage for Moderna COVID-19 Vaccine Booster

September 3, 2021

The FDA is deliberating between approving a booster shot of Moderna’s COVID-19 vaccine at a 50 microgram (mcg) level or at a current 100 mcg level, the latter being the level that make up the first two doses each of the vaccine.

On Wednesday, Cambridge, Mass.-based Moderna announced that it has asked the FDA to evaluate the booster dose at the 50-mcg level. The vaccine is formally known as mRNA-1273.

The company said it expects to submit data to the European Medicines Agency and other international regulatory authorities in the coming days.

“Our submission is supported by data generated with the 50-mcg dose of our COVID-19 vaccine, which shows robust antibody responses against the Delta variant,” said Moderna CEO Stéphane Bancel.

The company reported that in a phase 2 study with 344 participants who got a booster six months after their second dose, the 50-mcg dose boosted neutralizing titers significantly. The lowered dose would also address concerns that a 100-mcg booster shot may be more than is needed to achieve the required immune system response. — Martin Berman-Gorvine