Preliminary results of the first major round of serological testing in Israel show significant differences between various areas of the country and between different health maintenance organizations (HMO), a report said Wednesday evening.
The program, aimed at determining the extent of the population’s exposure to the coronavirus — currently and previously — kicked off in late June.
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 study, which in the first phase tested more than 70,000 people, showed that among those who belong to the Maccabi HMO, only one percent of those tested had antibodies, according to initial results published by the Kan public broadcaster.
For those in the Leumit HMO, the figure was 3%. However, the number jumped to 5% among those who are in the Meuhedet HMO in the Tel Aviv metropolitan area, and 8% among Meuhedet’s clients in Jerusalem, the report said.
Notably, the figures did not include the Clalit HMO, Israel’s largest.
Israel’s confirmed tally of cases stands at 56,085, roughly 0.6% of the country’s 9.1 million citizens.
The data showed much higher infection rates in known hotspots such as Jerusalem and Bnei Brak, and significantly lower rates in most other areas of the country.
Israel is very far from herd immunity, which requires some 60% of the population to have antibodies.
But the figures could mean that the disease is less lethal than thought, since there have apparently been far more cases than diagnosed so far, and the number of serious cases and deaths has not changed.
Tens of thousands of people are expected to be tested later as part of the next phase of the effort.
The antibody tests were performed on blood samples taken randomly from those who were having blood tests done at health clinics anyway. Samples were first taken from high-risk groups such as medical workers, the elderly, and those with underlying health issues.
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 future outbreaks.
Last month, Health Minister Yuli Edelstein said the antibody tests would give health officials a “better intelligence picture” on virus hotspots in the country.
The testing program was announced in early May by then-Health Ministry director-general Moshe Bar Siman-Tov, though it faced delays before starting.
The results of an initial set of serological tests, which were detailed in a report in early June, indicated that some 200,000 Israelis, or 2.5% of the population, had had COVID-19 by that time.
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 do not address whether the person still has the coronavirus or has recovered.
Agencies contributed to this report.