Pfizer/BioNTech say the updated Covid-19 booster produces “significantly greater” protection than the original vaccine.


Pfizer and BioNTech said on Friday that immune responses to the Omicron BA.4/BA.5 subvariants were “significantly greater” in people who received its new bivalent booster compared to people who received the companies’ original Covid-19 vaccine.

A bivalent booster targeting 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 produced about four times higher levels of neutralizing antibodies against the Omicron BA.4/BA.5 variants in people over 55 compared with the original vaccine. The data has not been peer reviewed or published.

When someone gets a vaccine, it can take a few weeks for immunity to build up and provide full protection. The data showed that one month after study participants received the new booster, Omicron BA.4/BA.5 neutralizing antibodies increased 13.2-fold from pre-booster levels in adults 55 and older, compared to a 2.9-fold increase in older adults. original vaccine For adults aged 18 to 55, neutralizing antibodies were 9.5 times higher than pre-booster levels.

The Omicron BA.5 subvariant has dominated US Covid-19 infections since July, but a mix of other Omicron variants is winning 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 the search for a bivalent COVID-19 booster, as soon as it becomes eligible, to maintain a high level of protection against the widely circulating Omicron BA.4 and BA..5 sublines,” he said. Pfizer CEO Albert Bourla said in a statement: “These updated data also add to the adaptability of our mRNA platform and our ability to quickly update the vaccine to match the most common strains each season.”

The companies’ new data comes after two small studies that measured immune responses about three to five weeks after the booster dose was updated; both found that the updated Covid-19 booster shots seem to work against the BA.4 and BA.5 Omicron subs as well as the original boosters they replaced. The studies were released as preprints and have not been peer-reviewed or published.

Pfizer and BioNTech are still conducting larger clinical trials of the updated promoters, and said they are continuing to test the vaccine against other variants of the virus.

Experts say the push this fall is still an important way to renew protection, even among people who have been previously infected or vaccinated. Children under 5 are eligible for updated boosters.

To date, 26.3 million people in the United States over the age of 5 have received updated Covid-19 boosters.

An analysis released in early October suggested that if more people in the US got the boost by the end of the year, about 90,000 Covid-19 deaths could be avoided this fall and winter. However, if vaccine uptake continues at the pace seen in early October, the US could see more than 1,000 Covid-19 deaths this winter, according to analysis by the Commonwealth Fund.