According to data published on the online archive bioRxiv, antibody levels against the variant increased nearly 9 times in older adults, aged 55 and over, who received the Omicron shot compared to a 2-fold increase in participants with the original shot.
As of 12 November, it was estimated that the BQ.1.1 variant, which is closely related to the BA.5 Omicron subvariant, was responsible for about 24.1% of the COVID-19 cases in the United States.
The bivalent shot, according to Pfizer and BioNtech, also triggered an immune response against more recent Omicron subvariants like BA.4.6, BA.2.75.2, and XBB.1.
The companies had just recently made data public that demonstrated their Omicron-tailored shot produced a stronger antibody response against BA.4/5 subvariants after one month in older adults than the original shot.
Omicron-tailored shots produced by Pfizer and rival Moderna Inc have already received US approval for use in adults and children as young as five years old based on data from pre-clinical studies.
Last week, Moderna Inc had claimed that its Omicron-tailored vaccines had improved immune responses against BA.4/5 sub-variants. when administered as a booster dose, compared to its initial shot.
(With inputs from Reuters)
