Pfizer Inc and its German partner BioNTech SE said on Friday their omicron-tailored shot produced higher virus-neutralizing antibodies in older adults against the emerging subvariant BQ.1.1 than its original vaccine.

Antibody levels against the variant rose nearly 9 times in older adults, aged 55 and above, who received the omicron shot compared to a 2-fold increase in participants with the original shot, according to data posted on the online archive bioRxiv.

BQ.1.1 variant, which is closely related to the BA.5 omicron subvariant, was estimated to account for about 24.1% of the COVID-19 cases in United States, as of Nov. 12.

Pfizer and BioNtech said the bivalent shot also produced an immune response against newer omicron subvariants including BA.4.6, BA.2.75.2 and XBB.1.

The companies had recently released data that showed their omicron-tailored shot produced a strong antibody response in older adults than the original shot after one month against BA.4/5 subvariants.

Based on data from preclinical studies, omicron-tailored shots made by Pfizer and rival Moderna Inc have already been approved in the United States for adults and for children as young as five years.