Up to 270,000 Israelis Had Coronavirus, New Study Concludes

Between 2 percent and 3 percent of the Israeli population has contracted the coronavirus, at least 10 times more than the number of confirmed cases. That is the conclusion of the first Israeli study based on a representative sample of serological (antibody) blood tests.

According to the researchers, this means that as many as 270,000 Israelis may actually have been infected by the virus, most without displaying any symptoms at all. Yet the antibodies in their blood indicate that they’ve been infected.

This paints a decidedly different picture than previous estimates made by other researchers, who believed that the confirmed cases – slightly more than 17,000 as of Monday – constituted the majority of those infected in Israel.

The survey was conducted for the Pandemic Task Force led by Prof. Daniel Cohen of Tel Aviv University’s School of Public Health, in cooperation with the National Center for Disease Control and the Magen David Adom blood service.

The researchers conducted serological tests on blood samples of 1,700 Israelis, culled to form a representative sample of the population in terms of age, gender and geographic location. Some of the blood samples came from healthy people who donated blood to MDA, while others were collected randomly as part of the routine monitoring conducted by the center for disease control (not necessarily to monitor the coronavirus).

The line for coronavirus testing in the Neveh Sha’anan neighborhood of Tel Aviv, May 31, 2020.Ofer Vaknin

The researchers used serological testing kits that have been validated as being 95 percent to 98 percent accurate. During the study the scientists discovered IgG antibodies, the type that appear a week to two weeks after exposure to the virus. When it comes to other viruses, these antibodies are linked to protection from re-infection, but with regard to the coronavirus it still isn’t clear what level of protection these antibodies provide, and for how long.

“The data arising from the survey is generally similar to the information and surveys we’ve seen in other places,” Cohen told Haaretz. “For example, we see that there’s a higher rate of exposure among men than among women. Among women the rate of infection is 1.2 percent, compared to 2.6 percent among men.” The survey also showed that the greatest rate of infection is among ages 40 to 59, with the rate in this age range 3.6 percent. Among those 0 to 19, the rate of infection was 0.8 percent.