Israel’s largest hospital is expected to launch a trial to determine the benefits of receiving a fourth dose of the Pfizer coronavirus vaccine, The Jerusalem Post confirmed.

The trial was first reported on by KAN News. It will be run by Sheba Medical Center at Tel Hashomer under the guidance of Dr. Gili Regev-Yochay, director of the Infectious Disease Epidemiology Unit at the hospital. It will look to see how much an additional shot raises a person’s antibody levels.

The volunteers, likely hospital workers who are already part of an ongoing antibody study at the hospital, will be tested several times before and after the fourth dose. The exact number of participants is still fluid.