JERUSALEM — Israel has begun trials of a fourth dose of coronavirus vaccine in what is believed to be the first study of its kind.

The trial began at Sheba Medical Center, outside Tel Aviv, with 150 medical personnel who received a booster dose in August receiving a fourth shot of the Pfizer/BioNTech vaccine. The staff receiving the additional dose were tested and found to have low antibody levels.

The trial came as Israeli officials have considered rolling out a second tranche of booster shots to its population as the country grapples with rising infections with the new omicron variant.

Prof. Jacob Lavee, former director of the heart transplant unit at Sheba, said “hopefully, we’ll be able to show here… that this fourth booster really provides protection against the omicron, which is highly needed.”

Israel rolled out a world-leading vaccination campaign early this year. Just over 4.2 million of Israel’s 9.3 million people have received a third dose of the Pfizer/BioNTech vaccine.

Israel has recorded at least 8,242 deaths from coronavirus since the start of the pandemic.