Professor Jacov Lavee receives a fourth dose of coronavirus disease (COVID-19) vaccine as part of a trial in Israel, as Health Ministry is considering offering the second booster to the elderly and immuno-compromised at Sheba Medical Center in Ramat Gan, Israel December 27, 2021. REUTERS/Ronen Zvulun

An Israeli heart transplant surgeon on Monday became the first to be jabbed with a fourth dose of the COVID-19 vaccine, in an unprecedented clinical trial to determine the efficacy of administering a second round of boosters amid the fast spread of the Omicron variant.

“It’s one small jab in the shoulder, but one giant leap for mankind in the global battle against the COVID infection,” said Prof. Jacob Lavee, the first participant in the study conducted at Israel’s Sheba Medical Center. “One of the main reasons that I decided to join this particular study in addition to the desire to be protected by myself is that I did not want to expose the heart transplantation patients that I am taking care to the potential of getting Omicron. That’s a real threat as based on our own research we know that their immunity following the third dose has diminished significantly so they are exposed.”

As part of the trial, a group of 150 Sheba health workers — who received the third vaccine dose before the end of August and have now shown serological results under the 700 mark — will get a fourth COVID-19 vaccine shot. About 80 of the 150 participants got their jab on Monday and the remainder will be vaccinated tomorrow, Sheba’s spokesperson said.

“The trial will zero in on efficacy of the vaccine in producing antibodies and safety, in order to ascertain if a fourth vaccine is needed in general,” according to Prof. Gili Regev-Yochay, the lead researcher of the study. “This research is expected to shed light on the additional benefits of administrating a fourth dose, and we will [aim to] understand whether, and to whom it is worth giving.”

In the coming days, all 150 volunteers will undergo serological testing to check their reaction to the vaccine shot and to test the antibody response.

Earlier this month, an Israeli Health Ministry panel of experts recommended administering a fourth dose of the Pfizer /BioNTech vaccine to those aged 60 and above who received a booster shot at least four months ago. However, a final approval by the ministry’s director-general is still pending.

Regev-Yochay will submit the results and recommendations of the study to Israel’s Health Ministry in about two weeks. The results are expected to help guide the Israeli government in deciding whether to roll out a second booster for the elderly and maybe to the general population.

“This research is very important, because we will have initial data within a few days about safety, and we will have a little bit of a basis on how much immunogenicity the fourth vaccine shot raises,” said Regev-Yochay, director of Sheba’s Infectious Disease Epidemiology Unit. “We will be more safe to recommend, that everybody who has immune suppression can go and get [a second booster], or if we see that we have outbreaks with severe disease in elderly homes, maybe we should decide to recommend them to [get another shot].

The Sheba study is conducted in conjunction with Israel’s Health Ministry and is approved by the Helsinki Committee which is in charge of validating human trials.