A program to carry out tens of thousands of serological tests aimed at determining the extent of the population’s exposure to the coronavirus began on Monday.
The Health Ministry, with the cooperation of the country’s health maintenance organizations, hopes to test some 70,000 people from 190 communities across the country.
Tens of thousands more will be tested later as part of the effort.
Tests will be performed on blood samples taken randomly from those who are anyway having blood tests done at health clinics. Samples will at first be taken from high-risk groups such as medical workers, the elderly and those with underlying health issues.
The tests can identify antibodies to the coronavirus, which can be present in the blood of those who caught the virus but did not develop any symptoms.
The antibody tests are seen as a key component in finding out who already had the disease in order to better understand its spread and shape policy ahead of a possible second outbreak.
On Sunday Health Minister Yuli Edelstein warned that the country was at the “beginning of a second wave.”
The number of daily infections has been steadily climbing since lockdown rules were eased in May, with cases diagnosed across the country. The Health Ministry on Monday afternoon recorded 492 new COVID-19 cases in the previous 24 hours.
Earlier this month Edelstein said the antibody tests would give health officials a “better intelligence picture” on virus hotspots in the country.
“That way we can better deal with an additional wave of coronavirus if, God forbid, it breaks out,” he said.
The testing program was announced in early May by outgoing Health Ministry director-general Moshe Bar Siman-Tov, though it has since faced delays.
The results of an initial set of serological tests, which were detailed in a report at the beginning of the month, indicated that some 200,000 Israelis, or 2.5 percent of the population, have had COVID-19 — more than ten times the confirmed number of patients.
The results indicate a far greater infection rate than previously thought — estimates by the Health Ministry and the National Security Council put the rate at no more than 1% of the population — but still nowhere near the 60% or so that is required to achieve herd immunity. They also indicate a far greater chance than previously thought for carriers to feel no symptoms.
Antibody tests are different from the nasal swab tests currently used to diagnose active infections. Instead, the tests look for blood proteins called antibodies, which the body produces days or weeks after fighting an infection. Most use a finger-prick of blood on a test strip. An antibody test might show if the subject had COVID-19 in the recent past, which most experts think gives people some protection.
The reliability of the tests is said to be between 95% and 98%. They don’t say whether the person still has the coronavirus or has recovered.
The government hopes that by conducting widespread serological testing, it will be able to determine if Israel is approaching herd immunity or if it is unprepared for a resurgence of the virus.
Bar Siman-Tov has said that if only a small percentage of Israelis are found to have COVID-19 antibodies, that could indicate the country’s health system may become swamped during a future outbreak.
The number of overall virus cases climbed to 23,989 on Monday, of whom 17,114 have recovered. Of the 6,556 active cases, 46 were in serious condition, with 24 on ventilators. Another 58 were in moderate condition and the rest were displaying mild or no symptoms.
With the new wave of infections showing no sign of abating, the government decided to limit public gatherings and reimpose some restrictions previously employed to stem the outbreak of the coronavirus.
Agencies contributed to this report.