The data was presented at a meeting of a ministerial group of immunization experts on Thursday and uploaded to its website on Sunday, although full details of the study have not been released.
The results were comparable to separate statistics reported last week by Israeli health care provider Maccabi, one of several organizations administering booster injections in an attempt to curb the variant of the delta coronavirus.
Israeli Prime Minister Naftali Bennet receives third dose of vaccine
Breaking down statistics from Israel’s Gertner Institute and KI Institute, ministry officials said that in people aged 60 and over, protection against infection provided from 10 days after a third dose was four times higher than after two doses.
A third jab for those over 60 offered five to six times the protection after 10 days in the event of serious illness and hospitalization.
This age group is particularly vulnerable to COVID-19 and in Israel it was the first to be vaccinated when the vaccination campaign began in late December.
In recent weeks, the health ministry said immunity has also waned over time for the elderly and young. Most of the vaccinated people who became seriously ill in Israel were over 60 and had underlying health problems.
Israel began giving the third injection to people over the age of 60 on July 30. On Thursday, it lowered the age of eligibility for a recall to 40, and included pregnant women, teachers and health workers below that age. The third doses are only given to those who received their second injection at least five months ago.
The United States has announced plans to offer booster shots to all Americans, citing data showing diminished protection. Canada, France and Germany have announced recall campaigns.
Battling an outbreak of the delta variant since June, Israel currently has one of the highest per capita infection rates in the world. Almost 1.5 million of the country’s 9.3 million people suffered a third stroke.