(Bloomberg) -- Moderna said that it had filed initial data with the US Food and Drug Administration for clearance of a third-dose booster shot of its COVID-19 vaccine.
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.
The company also said it planned to submit the data to regulators in Europe and elsewhere in the coming weeks.
A panel of expert advisers to the FDA plans to hold a meeting on booster shots on Sept. 17, according to people familiar with the planning.
The filing puts Moderna only slightly behind Pfizer and BioNTech in seeking official go-ahead for a third-dose booster. Those companies filed initial booster data with the FDA last month.
A debate over booster shots is intensifying in the US amid a rise in breakthrough infections and a broader delta-variant fueled surge in illness. Still, moving too quickly toward booster shots is controversial among scientists, 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 dose used in the Pfizer.
While Pfizer has moved forward with the same dose for its booster shot, Moderna has been testing a lower dose 50 microgram for third dose booster, believing that it will not necessarily need to use a achieve a robust immune response.
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