5 Fold Protection with Fourth Jab of COVID Vaccine, says Preliminary findings from Israeli Study

"This most likely means a significant increase in the protection against infection and severe hospitalisation and symptoms," he said alongside professor Galia Rahav, head of Sheba's infectious disease unit and lead of the study.

The trial began at Sheba Medical Center, outside Tel Aviv, with 150 medical personnel receiving a fourth shot of the Pfizer/BioNTech vaccine. They had all received their first booster shots no later than August 20 of last year and had antibody blood test readings under 700. All the participants in the trial have been undergoing blood testing to track their level of antibodies.

Prof. Gili Regev-Yochay said, "These preliminary findings are in addition to preliminary results received on side effects following the fourth dose and also indicate the safety of the fourth dose. This study will produce additional information in the days and weeks to come."

The researchers noted that about 80 per cent of the participants in the study reported a minor localized reaction to the vaccination. About 45 per cent reported symptoms such as weakness, muscle aches or a headache. Ten per cent reported a fever that in most cases subsided within a day.

Regev-Yochay explained that it appears at this stage that the fourth does is as safe as the prior three.

The researchers are yet to publish their findings soon.