It has been more than three months since random blood testing was undertaken to survey the presence of coronavirus antibodies among Israelis, but the results of the studies have not yet been published and are no longer relevant.
The first of the surveys, which were conducted to get a better sense of the extent of coronavirus infection in Israel, was carried out in the ultra-Orthodox Tel Aviv suburb of Bnei Brak, which has seen major spikes of the disease since the pandemic began. A total of 7,500 samples were taken there. Another more general survey obtained samples from 75,000 people in 191 communities throughout the country.
Israeli authorities invested millions of shekels in the effort, for the design of the study, the purchase of the testing kits, and to administer the tests and analyze them in laboratories. The project was launched in June in the hope that the epidemiological information would help gauge the possible presence of herd immunity among the population and to confirm which population groups were at the greatest risk of infection or of infecting others.
None of the survey findings, however, have yet been released. Haaretz has learned that so far only preliminary findings from the survey in Bnei Brak are available.
The epidemiological survey in Bnei Brak, which began first, focused on studying the dynamics of the spread of the virus in a densely populated area and involved the collection of 7,500 blood samples. One component of the Bnei Brak survey involved taking samples from people in their homes who had been infected with the virus, with the aim of providing information on how the virus is transmitted within the family, particularly to or from children. The second component of the Bnei Brak research involved a random sample of 4,500 residents of the Tel Aviv suburb based on criteria set in consultation with the Central Bureau of Statistics.
Haaretz has learned that the only information so far available are the preliminary results of the random sampling of the 4,500 Bnei Brak residents, which coincided with the end of the first wave and the beginning of the second wave of the pandemic in Israel. The data shows that about 7 percent of those randomly tested for antibodies in Bnei Brak were found to be infected.
But the findings are no longer relevant. At that time, there had been about 3,000 to 3,500 cases of the coronavirus diagnosed there, representing about 1.5 percent of Bnei Brak’s population. Now there have been more than 17,000 confirmed cases in the town, infecting nearly 9 percent of Bnei Brak’s residents.
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Some health-care system officials, including epidemiologists, acknowledge that findings from three months ago are now useless. For their part, however, Health Ministry officials agreed that the figures don’t reflect the current situation, but they said they intend to carry out another antibody survey in Bnei Brak to assess the change in the situation.
“It’s scandalous that the findings from the serological [blood testing] survey in Bnei Brak, which began even before the general survey, have not been released all this time,” one epidemiologist told Haaretz. “These findings are obviously completely irrelevant because the incidence of infection is so much more widespread.”
The results of the Health Ministry-sponsored national antibody survey, which was conducted with the assistance of the country’s four health maintenance organizations, have also not been officially released. Even before it began, it was harshly criticized by the head of the Central Bureau of Statistics, Prof. Danny Pfeffermann, who warned in late June that the sample would not be representative and would lead to false conclusions due to the manner in which individuals were selected for testing. “I suggested holding a thorough discussion of the issue, but to my surprise and disappointment, I didn’t receive any reply,” Pfeffermann said at the time.
The national sampling was of patients who went to HMOs for various kinds of other blood tests and who were asked to provide an additional sample for the coronavirus survey.
“Such a survey will not enable a scientific assessment of possible rates of error,” Pfeffermann said, and argued that the correct way to have sampled the population was with a random survey in which every Israeli had a chance, albeit not an equal chance, to be a subject of the sampling. It is reasonable to assume, Pfeffermann explained, that at least a portion of those sampled who went to their HMO clinics for a blood test were already suffering from some kind of medical condition. As a result, they may have been more careful than the general population about being exposed to the coronavirus, he said, meaning that the sample was not representative of the country’s population.
“To this, I would add that one of the goals of serological testing is to examine the interaction among people living in the same household, but the proposed testing does not allow for this. There is no doubt that it’s very convenient to sample this way, because the people are coming to the clinic in any event to give blood samples. But with all due respect, reliability should not be replaced with convenience,” he said at the time.
In early June, findings were published from a separate coronavirus blood sample survey conducted by the Health Ministry’s COVID-19 response team, led by Prof. Danny Cohen of Tel Aviv University’s School of Public Health, and with the involvement of Israel’s National Center for Disease Control and Magen David Adom’s blood services division. The research concluded that the rate of exposure to the coronavirus in Israel at the time was 2.5 percent of the population, a figure that reflected an infection rate 10 times the number of confirmed cases at the time.
That conclusion, which was drawn from the results of blood samples from some 1,700 Israelis, sparked major controversy and criticism from some experts regarding how the survey was carried out and the validity of the results.
The entire decision to conduct serological testing in Israel was met with mixed reactions. Public health experts believed the testing could provide valuable information regarding the spread of the virus that could not be obtained by other means. There were also those who argued, however, that the effort would be a waste of time and resources and that Israel could rely on the conclusions drawn from blood testing in other countries.