Moderna Inc. said that it had filed initial data with the U.S. Food and Drug Administration for clearance of a third-dose booster of its Covid-19 vaccine, adding fuel to a debate over the need for additional shots.
In a statement on Wednesday, the company said the booster shot, using a reduced dose of 50 micrograms that is half the dose used in the existing vaccine, raised antibody levels against the delta variant by more than 40-fold in a clinical trial.
Moderna said it planned to submit the data to regulators in Europe and elsewhere in the coming weeks.
The new filing puts the Cambridge, Massachusetts biotechnology company only slightly behind rivals Pfizer Inc. and BioNTech SE in seeking official go-ahead for a third-dose booster. Those companies filed initial booster data with the FDA last month.
Pressure on regulators to clear a path for more people to receive booster doses has been growing since last month, when the White House said that it wants to start getting additional shots to Americans starting Sept. 20.
A panel of expert advisers to the FDA plans to hold a public meeting on Covid booster shots on Sept. 17 that will focus on the Pfizer-BioNTech booster application, according to a statement from the agency Wednesday. The meeting will begin at 8:30 a.m. that day and will be streamed online.
“The FDA is evaluating data submitted by Pfizer-BioNTech in a supplemental Biologics License Application for its COVID-19 vaccine and will discuss it with the agency’s advisory committee,” Peter Marks, who heads the FDA center in charge of vaccines, said in a statement.
“Should the data received from other manufacturers raise unique questions that would benefit from the committee’s input, the agency intends to consider additional public discussions,” Marks said.
In late trading Wednesday in New York, Moderna shares advanced 0.7% after ending the regular trading session up 3.5%.
Wrangling over booster shots is intensifying in the U.S. amid a rise in breakthrough infections and a delta-variant fueled surge in illness. Still, moving too quickly is controversial, as there is little evidence that the capacity of vaccines to prevent serious illness, hospitalization and death has waned significantly.
In clinical studies, a third shot given to people who participated in Moderna’s original phase 3 trial more than six months after their first two shots boosted neutralizing antibodies significantly, according to results presented earlier this summer. There were no significant new side effects, the company said in an August earnings presentation.
The Moderna and Pfizer vaccines are based on similar messenger RNA technology, and have produced similar overall results, but there are subtle differences. In particular, Moderna’s current vaccine uses two 100 microgram doses, a higher amount than 30 microgram doses used in the Pfizer vaccine.
While Pfizer has moved forward with the same dose for its third booster shot, Moderna has also been testing a lower dose of 50 micrograms for a third dose booster, believing that it will not necessarily need to use a achieve a robust immune response.