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Thursday, November 12, 2026Nov 12

Pfizer booster spurs immune response to new omicron subtypes

FILE - Ryan Dutton, an EMT from Rescue Inc., prepares shots of the Pfizer COVID-19 booster vaccine during a vaccine clinic held by Rescue Inc. at Leland & Gray Middle and High School, in Townshend, Vt., on Tuesday, Sept. 20, 2022. The updated COVID-19 boosters aren't an exact match to the newest omicron mutants but Pfizer says lab tests suggest its shot may offer some cross-protection.  (Kristopher Radder/The Brattleboro Reformer via AP, File)
FILE - Ryan Dutton, an EMT from Rescue Inc., prepares shots of the Pfizer COVID-19 booster vaccine during a vaccine clinic held by Rescue Inc. at Leland & Gray Middle and High School, in Townshend, Vt., on Tuesday, Sept. 20, 2022. The updated COVID-19 boosters aren't an exact match to the newest omicron mutants but Pfizer says lab tests suggest its shot may offer some cross-protection. (Kristopher Radder/The Brattleboro Reformer via AP, File) FILE - Ryan Dutton, an EMT from Rescue Inc., prepares shots of the Pfizer COVID-19 booster vaccine during a vaccine clinic held by Rescue Inc. at Leland & Gray Middle and High School, in Townshend, Vt., on Tuesday, Sept. 20, 2022. The updated COVID-19 boosters aren't an exact match to the newest omicron mutants but Pfizer says lab tests suggest its shot may offer some cross-protection. (Kristopher Radder/The Brattleboro Reformer via AP, File)

Pfizer said Friday that its updated COVID-19 booster may offer some protection against newly emerging omicron mutants even though it’s not an exact match.

Americans have been reluctant to get the updated boosters rolled out by Pfizer and rival Moderna, doses tweaked to target the BA.5 omicron strain that until recently was the most common type. With relatives of BA.5 now on the rise, a question is how the new boosters will hold up.

Pfizer and its partner BioNTech said their updated booster generated virus-fighting antibodies that can target four additional omicron subtypes, including the particularly worrisome BQ.1.1.

The immune response wasn’t as strong against this alphabet soup of newer mutants as it is against the BA.5 strain. But adults 55 and older experienced a nearly 9-fold jump in antibodies against BQ.1.1 a month after receiving the updated booster, according to a study from the University of Texas Medical Branch in Galveston and the companies. That’s compared to a 2-fold rise in people who got another dose of the original vaccine.

The preliminary data was released online and hasn’t yet been vetted by independent experts.