JERUSALEM (Reuters) - Most people who received a third dose of Pfizer Inc's COVID-19 vaccine felt similar or fewer side effects than they did after receiving the second shot, according to an initial survey in Israel.

Israel began offering the booster shots about 10 days ago to people over age 60 as part of efforts to slow the spread of the highly contagious Delta variant. That effectively turned Israel into a testing ground for a third dose before approval by the U.S. Food and Drug Administration.