Bivalent booster is 4x better against BA.5 in older adults, Pfizer says

Pfizer reported Friday that the new bivalent COVID-19 booster spurred neutralizing antibody levels that were fourfold higher against the omicron subvariants than those seen after the original booster.

There are concerns about whether the updated booster is an improvement over the previous one. The fall booster campaign is still facing challenges. A shocking number of Americans are not getting the shot.

Better boost

The new booster shot will provide strong protection from severe COVID-19 and revive waning immune responses to SARS- CoV-2 according to experts. Some experts don't believe that the updated bivalent booster will offer a clinically meaningful advantage over the previous booster in preventing mild infections.

The new data from Pfizer and BioNtech doesn't directly address the question of whether bivalent-boosted people were less likely to get the disease than people who had the old booster. It is thought to represent a clinically meaningful difference in protection.

When we look at neutralization, fourfold is the cutoff. A vaccinologist at Mount Sinai School of Medicine in Manhattan said that fourfold seems to mean something.

Pfizer and BioNTech compared the antibody levels in adults older than 55 who received a fourth dose of the vaccine to the original vaccine. A month after the booster, the companies looked at the levels of antibodies. The two groups had the same blend of people who had evidence of a past outbreak of the disease and those who didn't.


The two groups had the same levels of antibodies at the beginning. They differed after the booster. The participants who received the bivalent booster saw their levels of neutralizing antibodies against BA.4/BA.5 rise 13.4-fold, while the participants who received the original booster only saw a 1.9-fold rise.

A group of 38 people from ages 18 to 55 saw a rise in their antibodies against BA.5/BA.5. The data of people who were given the original booster was not reported.

The companies reported that participants without prior infections had the biggest gains in neutralizing antibodies.


The data show that the vaccine works as planned in providing stronger protection against the omicron BA.4 and BA.5 sublineages.

The BA.5 is on the decline. The latest data from the Centers for Disease Control and Prevention shows that the long-reigning subvariant accounted for 39 percent of cases in the US this week. BQ.1 and BQ. 1.1 are poised to become dominant in the coming weeks. They account for about one-fifth of US cases.

It's not clear how the booster will perform against the new sublineages. Preliminary data shows it may be better than the original booster.

The potential of the booster will only be realized if people get it. The CDC says that only 8.4 percent of people who are eligible have gotten the vaccine.

"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 sub lineages,"