Fewer than 0.01% of people who received Pfizer's COVID-19 vaccine have contracted the virus more than a week after receiving the second dose, the Maccabi health fund said on Monday.
The preliminary results shared by the HMO showed that only 20 people out of some 128,600 who received both shots have since been infected with the COVID-19 virus though none became even moderately ill.
Israel is a world leader with its rapid vaccine rollout, though the data also comes during a nationwide lockdown that has been helping to stem contagion. Israelis began receiving first shots of Pfizer's vaccine on Dec. 19.
The country is providing Pfizer with weekly data updates on its vaccine campaign under a collaboration agreement that may help other countries fine-tune their own inoculation drives.
"According to Maccabi's experts this is preliminary data but the numbers are very encouraging," Maccabi said in a statement.
"Maccabi reports that out of the 20 people infected, 50% suffer from chronic illnesses. All patients experienced a mild illness with symptoms including headaches, cough, weakness or fatigue. No-one was hospitalized or suffered from a fever above 38.5 C. Most patients tested for COVID-19 due to exposure to a verified patient," it said.
Anat Ekka Zohar, Maccabi's Information and Digital Health Division director, said "the fact that the infected patients came from different profiles is consistent with Pfizer's trial results."
"We will monitor these patients closely in order to examine if they continue to suffer from mild symptoms only and do not develop complications as a result of the virus," she said.
More than 2.6 million Israelis have received a single dose of the vaccine and about 1.2 million have been given both shots, out of a population of about 9 million.
Israel has reported about 600,000 virus infections and 4,478 deaths since the start of the pandemic.