Extreme close-up photo of a gloved hand holding a tiny jar.
Enlarge / A vial of the current Moderna COVID-19 vaccine.

Moderna reported Wednesday that a combination COVID-19 booster dose that targets the ancestral strain of SARS-CoV-2 and the initial omicron variant, BA.1, appears to surpass the current booster against both of those versions of the virus.

Moderna says the combination booster increased the amount of neutralizing antibodies against omicron 8-fold.

The vaccine maker wants this shot to be the go-to booster this fall. The company plans to submit its data to the FDA in the coming weeks and hopes to have the bivalent booster available by the fall.

This dose is the second bivalent design that can beat the current booster. The company reported in April that a bivalent booster targeting the ancestral strain could beat the current one. The data made it clear that the company would focus on bivalent boosters.

The CEO of Moderna said they were thrilled to share the preliminary data analysis. We anticipate more durable protection against variant of concern with the first bivalent booster candidate, and it's our lead candidate for a fall booster.

Boosted uncertainty

There is a lot of uncertainty about the fall booster campaign. It's not clear if the disease will be a seasonal one. The idea of a fall booster campaign has been accepted by vaccine makers, regulators, and experts.

The FDA's panel of independent experts will meet on June 28 to plan for the fall and future. Advisers will discuss whether or not the composition of the COVID-19 vaccine should be changed. The guidelines for deciding the formulas for yearly flu shots and the Vaccines and Related Biological Products Advisory Committee will be similar. Some data will be presented at the meeting.


The meeting is going to be very difficult. If vaccine makers want to have booster doses ready for the fall, they need to have the design selected and manufacturing started as soon as possible. The data that is used to guide the design decisions will be very limited. Moderna's newest bivalent booster is based on the BA.1 omicron subvariant, which is no longer in use in the US. The two subvariants that have already reached dominance are BA.2 and BA.2.12.1. The current version of omicron, BA. 2.12.1, appears poised to be overtaken by two additional subvariants, BA.4 and BA.5.

Varying variants

There are concerns that the current vaccine design may not be as effective as it could be due to the fact that the newer subvariants can be difficult to evade.

Moderna didn't give any data on how well the vaccine works against omicron subvariants. It is not clear if the data would be relevant for the fall. It is possible that subvariants could be circulating by the winter.

Even if efficacy is dinged by new subvariants, the new omicron-based bivalent booster will still be effective, according to the President of Moderna.

The data we have shows that the booster should be updated with this design. "We think it's important to update the sequence of the vaccine with an omicron- containing variant because of the ability to achieve significantly higher titers, which we think will correlate with better durability and better protection against omicron subvariants during the winter."

Moderna doesn't have any data to support that. It looks like the data it has is strong enough to protect against BA.1 and surpass the original booster.