Tel Aviv, July 13 (IANS) Israel's Health Ministry has instructed four health maintenance organisations to start offering the third doses of the Covid-19 vaccine for adults with weak immune systems.

The direction on Monday came a day after Health Minister Nitzan Horowitz announced the move on Sunday, saying the Ministry is looking into the possible authorisation of booster shots to the general public, reports Xinhua news agency.

The move came amid Pfizer's request to the regulators of the US and Europe for approving a booster dose of its vaccine.

The ministry has reported a steady rise in the number of infections driven by the spread of the Delta variant.

On Sunday, 423 new cases were diagnosed across Israel.

About 61 percent of the country's 9.3 million citizens have been vaccinated with at least one dose, and about 55 per cent with two doses.

Most of them received the Pfizer vaccine.

--IANS ksk/