January 26, 2022
Covid-19 vaccine-makers have been updating their shots to better match Omicron in case health authorities decide a change is needed.
FILE - Pharmacist Sima Manifar prepares a children's dose of the Pfizer COVID-19 vaccine during a vaccination clinic at City of Lawrence's "The Center," which serves seniors, families and the community, Wednesday, Dec. 29, 2021, in Lawrence, Mass. Pfizer has begun a study comparing its original COVID-19 vaccine with doses specially tweaked to match the omicron variant. Pfizer and its partner BioNTech announced the study on Tuesday, Jan. 25, 2022. (AP Photo/Charles Krupa)