Pfizer and BioNTech said Friday that the immune responses against Omicron BA.4/BA.5 subvariants were “substantially higher” in people who got its new bivalent booster compared with people who received the companies’ original Covid-19 vaccine.
The bivalent booster that targets the original coronavirus strain and the Omicron BA.4 and BA.5 subvariants became available in the US in early September. Pfizer and BioNTech said in a news release that the bivalent booster generated about four times higher levels of neutralizing antibody against the Omicron BA.4/BA.5 variants in people older than 55, compared with the original vaccine. The data has not been peer-reviewed or published.
When someone gets any vaccine, it can take a few weeks to build up immunity and generate its full protection. The data showed that a month after study participants got the new booster, Omicron BA.4/BA.5 neutralizing antibodies increased 13.2 fold from pre-booster levels for the adults 55 and older, compared with a 2.9 fold increase in older adults who got the original vaccine. For adults ages 18 to 55, neutralizing antibodies were 9.5 fold higher than pre-booster levels.
The Omicron BA.5 subvariant had dominated US Covid-19 infections since July, but a mix of other Omicron subvariants have been gaining against it. BA.5 now accounts for 49.6% of new infections in this country, according to data from the US Centers for Disease Control and Prevention.
“As we head into the holiday season, we hope these updated data will encourage people to seek out a COVID-19 bivalent booster as soon as they are eligible in order to maintain high levels of protection against the widely circulating Omicron BA.4 and BA.5 sublineages,” Pf …