Israel Finds Fourth Pfizer Dose Produces Five-fold Increase in Antibodies, as Country Prepares to Launch Moderna Fourth Shot Trial Infectious Diseases 04/01/2022 • Maayan Hoffman Share this:Click to share on Twitter (Opens in new window)Click to share on LinkedIn (Opens in new window)Click to share on Facebook (Opens in new window)Click to email this to a friend (Opens in new window)Click to print (Opens in new window) Israeli Prime Minister Naftal Bennett (right) is briefed about Sheba Medical Center’s COVID-19 fourth shot trial on Tuesday, January 4, by hospital Director-General Prof. Yitshak Kreiss. A fourth shot of the Pfizer coronavirus vaccine administered to individuals who received their third shot nearly five months ago produces a five-fold increase in antibodies, according to preliminary results of a first-in-the-world trial being conducted in Israel. The news comes on the same day that the country announced it would launch a trial to determine the effectiveness of receiving a fourth shot of the Moderna coronavirus vaccine beginning on Wednesday. Both trials are being run out of Sheba Medical Center at Tel Hashomer and include around 150 medically personnel who received their third doses by August 2021, with a serology result below 700. Participants in the Pfizer trial were inoculated a week ago. The hospital announced the preliminary results on Tuesday during a visit to the facility by Israeli Prime Minister Naftali Bennett. The data has not yet been published. Fourth Pfizer shot increases antibodies five-fold “I am pleased to announce … that the initial research indicates that within one week of receiving the fourth vaccine, there is a nearly fivefold increase in the number of antibodies in the blood,” Bennett said. “[A fourth booster] will probably provide a much higher level of protection than without the shot – a high level of protection for both infection and severe morbidity. In simple terms, the fourth vaccine is safe, it must be. The fourth vaccine is very likely to work.” He added that in the two days since Israel opened up fourth doses, more than 100,000 Israelis registered to be vaccinated or have already been vaccinated. Israel is the first country in the world to offer a fourth shot to all citizens over the age of 60 and medical workers who received their last doses at least four months prior. Chile also announced last month that it would offer citizens a fourth coronavirus vaccine dose, also starting with those who are at highest risk of infection or developing severe disease, but those shots are not expected to begin until February and they are being given only after six months have passed from the previous jab. Brazil also has approved a fourth shot, but only for the immunocompromised. Researchers say fourth dose safety profile is as good as expected Prof. Gili Regev-Yochay, director of the Infection Prevention and Control Unit at Sheba, is overseeing the trial. She stressed that the safety profile of the fourth shot appears similar to the profile in the previous doses. “These initial findings join the preliminary results on potential side effects, which were obtained following the administration of the fourth dose, which also indicate the safety of the fourth dose,” said Regev-Yochay. “This study will yield more information in the coming days and weeks.” The Moderna trial is being run in collaboration with Medison Pharma, a company that markets the Moderna vaccine in Israel. Participants will be medical workers who received three shots of Pfizer and will now receive a dose of Moderna. Researchers will be evaluating the degree of immunity and protection against the Omicron variant with this combination. Both trials are being run on conjunction with Israel’s Health Ministry and with full approval of the Helsinki Committee. Image Credits: Sheba Medical Center. Share this:Click to share on Twitter (Opens in new window)Click to share on LinkedIn (Opens in new window)Click to share on Facebook (Opens in new window)Click to email this to a friend (Opens in new window)Click to print (Opens in new window) Combat the infodemic in health information and support health policy reporting from the global South. Our growing network of journalists in Africa, Asia, Geneva and New York connect the dots between regional realities and the big global debates, with evidence-based, open access news and analysis. To make a personal or organisational contribution click here on PayPal.