An employee at the Mainz vaccination center draws up a syringe with the Comirnaty vaccine from Biontech and Pfizer, adapted to the Omicron BA.1 variant.
Sebastian Christoph Gollnow dpa | Picture Alliance | Getty Images
Pfizer said his Omicron booster elicits a stronger immune response against a range of emerging Covid subvariants circulating in the US
The booster shot elicited more antibodies against the Omicron sublines BQ.1.1, BA.4.6, BA.2.75.2 and XBB.1 than a fourth dose of the original one, according to new data the company released on Friday vaccines . Antibodies are an important part of the immune system that prevent the virus from entering cells.
Pfizer developed its booster against omicron BA.5 on behalf of the Food and Drug Administration. BA.5 was the dominant Covid strain in the US during the summer but is now disappearing as subvariants like BQ.1.1. start to become more dominant.
BQ.1.1 and its sibling BQ.1 currently cause about 48% of new infections in the United States, according to data from the Centers for Disease Control and Prevention. BA.5 has now fallen to around 25% of new Covid cases. BA.4.6 and BA.2.75.2 still account for a very small fraction of new infections, while XBB.1 is not yet present in sufficient numbers to show up in the data.
Antibodies against BQ.1.1 were about nine times higher in people who received an Omicron booster vaccine, while they were about twice as high in people who received a fourth dose of the original vaccine. Among the new subvariants, the Omicron booster elicited the strongest immune response against BA.4.6 with 11-fold higher antibodies and the weakest response against XBB.1 with about 5-fold higher antibodies.
The booster elicited the strongest immune response against omicron BA.5, the variant it was developed against, with a 13-fold increase in antibodies in people over 55, data previously published by Pfizer shows.
Modern said Monday that its Omicron booster elicits an immune response against BQ.1.1, although the company didn’t provide specifics.
US health officials have said that the boosters should offer better protection against the emerging subvariants since they are all Omicron and many descended from BA.5.
Pfizer and Moderna’s new boosters target both Omicron BA.5 and the original Covid strain that emerged in Wuhan, China in 2019. The original vaccines only targeted the first strain of Covid, and their effectiveness against infections and minor illnesses as the virus has evolved in recent years has declined significantly.