Pfizer said Wednesday that a booster dose of its COVID-19 vaccine may offer important protection against the new omicron variant even though the initial two doses appear significantly less effective.
Pfizer and its partner BioNTech said that while two doses may not be protective enough to prevent infection, lab tests showed a booster increased by 25-fold people’s levels of virus-fighting antibodies against the omicron variant.
Blood samples taken a month after a booster showed people harbored levels of omicron-neutralizing antibodies that were similar to amounts proven protective against earlier variants after two doses.