Israel on Sunday began offering a COVID-19 booster to children as young as 12, and its prime minister said a campaign that began a month ago among the older population has slowed a rise in severe illness caused by the Delta variant.
Announcing the decision, top Israeli health officials said people are 10 times more protected after the third vaccine dose.
Those eligible for the third shot can receive it provided at least five months have passed since their second jab - a timeframe shorter than an eight-month interval in effect in the United States.
So far 2 million people out of a population of 9.3 million have received three doses.
Israel and other countries have pressed ahead with booster plans despite opposition from the World Health Organization, which said more of the world should be vaccinated with a first dose before people receive a third.