A fourth dose of Pfizer’s coronavirus vaccine showed dwindling effectiveness against the Omicron variant, according to a trial conducted in Israel, with one its lead researchers saying the immunization is simply “not good enough.”
A study involving 154 medical staffers at Sheba Medical Center near Tel Aviv found that a fourth shot gave only marginal protection against the Omicron strain compared to previous mutations.
“We see an increase in antibodies, higher than after the third dose. However, we see many infected with Omicron who received the fourth dose,” said Gili Regev-Yochay, one of the head researchers on the trial, adding that while “the vaccine is excellent against the Alpha and Delta [variants],” for Omicron “it’s not good enough.”
Despite the new findings, Israeli health officials already moved ahead with fourth doses for the elderly, the immunocompromised and medical workers beginning earlier this month, with some 500,000 receiving a second booster on top of an initial two-dose regimen as of Sunday.