Booster spurs immune response to new subtypes

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.