Until now, scientists didn’t know whether vaccines would stop transmission and were banking only on it preventing severe illness and death. Pfizer itself has not published any data showing how the jab affects the spread of the disease.

Developers of other vaccines have also not offered any proof that their vaccines will be able to reduce transmission of the virus.

The survey done on 102 hospital staff in Israel is the first indication that a Covid-19 vaccine may stop transmission. It saw all but two of them develop antibody levels that were even higher than patients who had recovered from Covid-19.

Antibodies are substances produced by the immune system which store memories of how to fight off a specific virus.