Israeli President Isaac Herzog received a third shot of coronavirus vaccine on Friday (July 30), kicking off a campaign to give booster doses to people aged over 60.
The booster campaign makes Israel a testing ground for a third dose, before it's approved by the U.S. Food and Drug Administration.
Israel was a world leader in the vaccine rollout, and around 57% of the population has been double-vaccinated.
Prime Minister Naftali Bennett said Israel would share all the information it gleans from the rollout.
"The fight against the COVID pandemic is a global fight. The only way we can defeat COVID is together."
Bennett says Israel has already given 2,000 immunosuppressed people a third dose with no severe adverse events.
Since the emergence of the more contagious Delta variant, the health ministry has twice reported a drop in the vaccine's efficacy against infection and a slight decrease in its protection against severe disease.
Daily new infections have spiked to more than 2,000, up from a handful of cases per day a few months ago.
Israel's government hopes stepping up inoculation efforts will help avoid further costly lockdowns.