One in seven Bnei Brak residents has been infected with the coronavirus, according to a new antibody survey, prompting some experts to say it is poised to become the first Israeli locale with a degree of collective immunity.
In the predominantly ultra-Orthodox city near Tel Aviv, notorious as one of Israel’s top COVID-19 hotspots, doctors took blood from residents aged 7 and above, and found that in the most recent sampling, 13.8% had the antibodies common to recovered virus patients.
In August, when this sampling — the end of a three-month survey — took place, 5.6% of the population had been confirmed infected with coronavirus. This suggests that only around one in three people locally who caught the virus got tested and was included in official statistics.
Tel Aviv University immunologist Mordechai Gerlic told The Times of Israel that, as the survey of just over 8,500 people was concluded before the worst of Israel’s second wave, he thinks the figure will have grown to 30% by now.
He rejected the term “herd immunity,” saying it denotes very high immunity levels, but said that if such a large part of the population has antibodies, it could significantly slow virus spread there. The coronavirus could become “endemic” locally, by which he means present at a stable rate.
“I think they are close to a point at which much of the population there won’t spread the virus, the risk of catching the virus will be low, and high-risk people will be able to go out,” said Gerlic, a serology expert, who was not part of the latest research. “I would call this a point at which the virus is endemic.”
But Daniel Cohen, a Tel Aviv University epidemiologist and one of the directors of the new research, rejected any conclusion of community protection. “It’s very dangerous to think of herd immunity and protection in this situation,” he told The Times of Israel.
Cohen believes that antibody incidence will not have grown by more than a few percent since August, and also rejected the notion of protection until a high percentage is reached. “The bottom line is that the level of immunity is still very low,” he said.
Drawing a very different conclusion to Gerlic, who thinks that other cites may become “endemic,” Cohen thinks that if even Bnei Brak is not at an antibody level nearing herd immunity, nowhere in Israel is on the path. “You would have thought that in, at least, Bnei Brak there may be prevalence that may bring you close to community protection, but even here you don’t,” he said.
Cohen believes that the research highlights the high contagiousness of the coronavirus in households. In homes where there was at least one confirmed patient, almost half of family members — 47% — were shown to have caught the virus. “This highlights the importance of isolating people who are infected within their household, away from other family members,” he said.
The survey found that around 1 in 5 of the respondents who had tested positive for the coronavirus with swab screening didn’t show signs of antibodies.
Cohen said this should be taken at face value and indicates that not everyone produces antibodies — though he stressed this does not necessarily denote a lack of immunity as the ability to fight a virus is also derived from other “markers” including t-cells.
But Gerlic pointed out that the new survey tested for just one antigen, and there are several, and also noted that serological test processes have a margin of error. He believes that almost everyone produces antibodies, and that this would show if tests were conducted at higher accuracy rates, and if all antigens were tested.
Gerlic said the fact that a large majority of residents who were confirmed positive showed antibodies is further evidence that the immune system responds well to the coronavirus. “We see from this that the immune system acting normally with the coronavirus like with other viruses; we finally see there is nothing new, in this sense, about this virus,” he said.