Moderna's omicron booster triggers stronger response against subvariants than its original shot, company says

Just a few weeks after the FDA recommended that COVID-19 vaccine manufactures tweak their boosters to zero in on the omicron BA.4 and BA.5 subvariants, Moderna has unveiled promising new data for its prospect.

On Monday, the mRNA specialist said its omicron-containing bivalent booster elicited higher neutralizing antibody responses compared with the current booster. After one month, trial participants who received the bivalent booster had BA.4 and BA.5 neutralizing antibodies that were 1.69 times higher than those who received the original booster, the company said.

The data has been shared with regulators and submitted for peer-reviewed publication. The company is working with regulators to advance two bivalent vaccine candidates based on various market preferences.

“This superior breadth and durability of immune response following a bivalent booster has now been shown in multiple phase 2/3 studies involving thousands of participants,” Moderna CEO Stephane Bancel said in a statement.

Moderna’s two candidates include one expected to have demonstrated “significantly higher titers” against the BA.4/5 variants, while the other is based on the BA.4/5 strain and is being developed “consistent with recent FDA advice," the company says. Both candidates contain 25 nanograms of the current booster and 25 nanograms of an omicron subvariant.

Last month, the FDA said that companies should tweak their boosters to target the infectious omicron subvariants. The companies don't need to make changes to their primary vaccine series, as primary doses provide a “base of protection” against serious outcomes, the FDA said.

The government's goal is for the updated boosters to be on the market by the fall of this year. Moderna previously forecasted a launch date of October or early November, while Pfizer said its shot could be ready by early October, The New York Times reported.