Israel testing fourth Pfizer COVID vaccine shot

An Israeli hospital launched a clinical trial Monday on the impact of a fourth shot of the Pfizer-BioNTech coronavirus vaccine, as the health ministry weighs a national fourth jab rollout.

The study being conducted by Sheba Medical Center involves 150 volunteers from the hospital's staff, who are at least four months removed from their third vaccine shot and have signs of waning antibodies.

The director of the Infectious Disease Epidemiology Unit at Sheba, Gili Regev-Yochay, said the study would assess the potential antibody boost from a fourth shot, any adverse effects and whether an additional booster reduces the risk of infection.