Omicron boosters better at preventing COVID infection than previous shots: CDC

by Joseph Choi - 11/22/22 2:51 PM ET

A Jackson-Hinds Comprehensive Health Center nurse loads a syringe with a Moderna COVID-19 booster vaccine at an inoculation station next to Jackson State University in Jackson, Miss., Friday, Nov. 18, 2022. (AP Photo/Rogelio V. Solis)

New data from the Centers for Disease Control and Prevention (CDC) shows that the updated, bivalent COVID-19 boosters provided better protection against infection when compared to multiple doses of the original mRNA COVID-19 vaccines.

The study, conducted between September and November, analyzed more than 360,000 viral tests for adults. The tests came from nearly 10,000 retail pharmacy locations and only included adults who had symptoms of SARS-CoV-2 and did not have immunocompromising conditions.

Findings from the CDC study indicated that the bivalent booster shots from Pfizer and Moderna, made to specifically protect against the BA.4 and BA.5 omicron subvariants, provided stronger protection when those who received it were compared to people who only received two, three or four doses of the original monoclonal vaccine.

Among the individuals in the study who tested positive for COVID-19, 72 percent had received two, three or four doses of the monoclonal vaccine and 5 percent reported having received the bivalent booster.

The bivalent booster doses were authorized without human data, and the findings of the study represent some of the first reports of the shot’s efficacy.

White House chief medical adviser Anthony Fauci commented on the findings of the study in a press briefing on Tuesday. Currently, only about 11 percent of eligible people have received an updated booster.

“It is clear now, despite the initial bit of confusion, that the BA.4-5 bivalent booster, what we refer to as the updated vaccine, clearly induces a better response against BA.4-5 and sublineages of BA.4-5 than does the ancestral strain,” Fauci said. “So we know it’s safe. We know that it is effective.

The majority of the tests were conducted at a time when the BA.4 and BA.5 subvariants were dominant in the U.S. The most recent federal data now indicates that BA.5 accounts for roughly a quarter of cases, with its viral descendants BQ.1 and BQ.1.1 each making up about the same proportion of total infections.

Recent data from Pfizer has indicated that the updated booster still offers strong protection against sublineages of BA.4 and BA.5.