The Health Ministry plans to begin administering some 200,000 blood tests to detect the presence of coronavirus antibodies by the end of the month. The tests should provide authorities with a better picture of exposure to the virus and may help prepare for a possible second wave of infections, as well as contributing to the development of a vaccine.
While most of the tests will be administered at HMOs throughout the country, about 7,500 of the tests are earmarked for Bnei Brak, the ultra-Orthodox town which was particularly hard hit by the virus. The new blood testing survey there has been dubbed Bnei Brak First and will include blood tests for residents age seven and up in households with confirmed cases, in addition to random testing of a representative sampling of the local population.
Because of the young population of the town, the testing there may also help shed light on a question of global interest: The role of children in the spread of the coronavirus.
Those tested will fill out a questionnaire that will provide information about the symptoms experienced by members of the household and who experienced them first. The blood, or serological testing, is part of a joint effort being conducted by the Gertner Institute, which is affiliated with the Health Ministry, the Bnei Brak municipality, the country’s health maintenance organizations, the Central Bureau of Statistics and researchers from Tel Aviv University.
“The sampling in Bnei Brak is important, not only to know what happened in Bnei Brak but also for the state of Israel in general,” said the ministry’s Dr. Boaz Lev, who is on the project’s leadership team, “to set future policy in the event we experience a second wave of an outbreak.”
“The more we understand the scope of the exposure in an event like this, the more appropriate and precise our response to it can be,” Lev added, noting that the tests will make it possible to ascertain the extent to which the disease spread in households with a confirmed patient as well as its impact around individuals who were infected but remained asymptomatic.
The project is being led by Prof. Daniel Cohen, who heads the school of public health at the Sackler School of Medicine at Tel Aviv University. “The survey in Bnei Brak is an attempt to obtain a picture of an area with intense exposure to the virus and to study the dynamics of infection in families [and] buildings, before and after the lockdown, [and] the scope of infection among such a dense population,” Cohen explained.
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The serological testing will also provide information on the extent to which exposure to the virus has given the population a measure of immunity to future infection, Cohen said. “It’s not just a matter of finding antibodies but also a quantitative analysis of them.” Over time, he explained, the quantitative tests will be able to teach the researchers if in fact the antibodies provide protection against the virus. The timing of the blood sampling, at the end of May, is optimal, he added.
“It will enable us to catch everything that happened in the months of March and April,” Cohen noted. “We will be able to obtain maximum evidence of exposure through the appearance of the antibodies” because it takes several weeks following exposure for a large quantity of antibodies to appear.
“There’s a major question mark in the world on the subject of the infection of children and the spread of the virus by children,” Cohen added. “The fact that Bnei Brak has a young population with a lot of children provides us a special opportunity to see what the role of children is.”
Much effort has been invested at the Bnei Brak municipality to carry out the survey, Cohen noted. At the same time that the Bnei Brak sampling is proceeding, there will be national testing involving the Health Ministry, the country’s HMOs, testing labs and teams of experts. The national testing will be carried out with a sample of patients coming to their HMOs for routine blood tests. At this stage, the blood tests slated for use are undergoing validation at the ministry’s main virus lab. That is to be followed shortly by training at the country’s HMOs own labs.
“The testing is based on the existing blood test infrastructure,” said Morris Dorfman, who heads the ministry’s regulatory division. “Those coming for a blood test will be asked to give an additional sample to test for antibodies and will be asked to answer a short background questionnaire,” he said. “The tests will be sampled based on defined sample groups to maintain a representative mix of all of the population groups. Following approximately 100,000 tests, we will be able to see for which of these defined groups we have reached our quota and can stop sampling and for which more is required.” Additional sampling may need to be conducted on people in their homes, he said.
The antibody testing may provide information that can be used to develop a vaccine, although there is still not enough information on the body’s immune defenses against the virus. So far, it is known that the immune system produces two kinds of antibodies in response to the coronavirus. The first, called IgM, appears three to five days after a patient is infected. The second, IgG, appears a week or two weeks after the infection. It remains for a more considerable period of time and is linked to the body’s immunological memory.
Nevertheless, at this stage it is not known how effective the IgG antibodies are in defending against the virus – or how long the antibodies provide a defense, or whether people who have recovered from the virus are immune from being infected again. Such information is critical because even if a vaccine is developed that prompts the body to produce antibodies found in patients who have recovered from the virus, it is still not clear the extent of protection this would provide. Doctors in Israel and elsewhere are using blood plasma from recovered coronavirus patients on an experimental basis to treat new patients, but it is not yet clear the extent to which this contributes to their recovery. About 20 percent of the plasma doses used have contained only minuscule amounts of the antibodies and are of no value to the immune system, experts have said. Researchers are therefore hoping that the blood testing project – which includes a quantitative measure of the presence of antibodies – will contribute to research on the body’s immunological defenses against the virus.