TEL AVIV—Israel began administering a booster shot of Pfizer Inc.’s Covid-19 vaccine Monday to people with weak immune systems, as it confronts an outbreak of the virus’s highly contagious Delta variant.
Israel’s Health Ministry said a third dose of the Pfizer vaccine would be offered to immunocompromised individuals, such as those who have undergone organ transplants. The step follows evidence that the additional shot might increase such patients’ antibody counts, according to a Health Ministry letter sent to Israeli healthcare providers.
Israel is one of the first globally to approve a booster shot after fully inoculating more than 80% of adults in the country with two doses of the Pfizer vaccine since starting its campaign in December. Pfizer said last week it planned to seek clearance from U.S. regulators to distribute a booster shot.
The Israeli Health Ministry said the recommended time between a second and third shot would be eight weeks, with a minimum gap of four weeks. The government said it was weighing whether to offer a third shot to the wider population.
Israel’s decision to give a third shot comes amid an outbreak of the Delta variant. New cases in Israel have risen to a seven-day average of 450 on Monday from around 10 a day for most of last month.