Maccabi Health Services studied a sample group of 50,777 people over the age of 60 inoculated in late December and then again in mid-January. Raw data showed that two days after the second shot, the number of new infections and hospitalizations were both down about 60% from their peak, researchers reported.

Trends began to shift around two weeks from the first dose, according to the analysis Maccabi’s KSM Research and Innovation Center did in collaboration with Israeli computational health researchers KI Institute.

A separate Israeli study of health workers who received two doses of the Pfizer Inc. shot found elevated levels of antibodies in nearly every participant that matched or exceeded clinical results.

Israel has been largely using Pfizer’s vaccine since it began its immunization drive in late December, with Prime Minister Benjamin Netanyahu offering data on the campaign to expedite and expand shipments. The country has been adhering to Pfizer’s guidance of a second shot about three weeks after the first, reserving second doses.

So far about 2.5 million people, or more than a quarter of the population, have received a first dose, with almost a million more getting the second. Children under 16, who have not been approved to take the vaccine, account for about 30% of the country’s 9.3 million people.

The country is currently in the midst of a third lockdown that began in late December to control a resurgence of the outbreak. In total, Israel has had nearly 600,000 cases and more than 4,360 deaths.