The results, according to Schlesinger, “can be used when making political decisions for the country.”

“A third were tested for up to three weeks after the onset of the disease and apparently had not yet developed antibodies,” Schlesinger explained. But the other two-thirds had contracted the disease more than four months previously, and their antibodies appear to have gone down.

“The study showed [that children] reach a peak antibody level for up to three months after diagnosis, ”he said. “Subsequently, a significant quantitative drop in antibodies was observed – more than in adults. These results may indicate that children have a weaker long-term immune response. “

According to Schlesinger, the disappearance of the antibodies does not mean that these children are not protected, but “it raises questions about their protection,” he said. This is especially the case because separate studies have shown that a correlation between the likelihood of infection is greater as antibody levels decline.

The study could also have important implications for understanding herd immunity, for the possibility of a recurrence of a reinfection wave and for vaccine considerations for young children, he said.

Another interesting finding from the study is that 10% of children were infected with the virus, although 41% of these children were exposed and knew they had been sick.

Schlesinger said the hospital is continuing the study and that a subsequent study conducted in June and July 2021, which is being written but has yet to be published, found the percentage of children in Jerusalem infected by the virus increased by 10% to 30% or even slightly more.

The ministries of health and education on Monday launched a series of serological tests among students in haredi (ultra-Orthodox) neighborhoods to determine the percentage of children who may have already had the corona. Departments have hinted that they expect 25-30% of them to have been infected. Children who have antibodies will receive a Green Pass and will be exempt from isolation if a member of their class becomes ill.

Finally, the study showed that opening schools did not increase infection rates in children, in that there was no over-prevalence of antibodies in children who, for various reasons , continued to attend educational institutions during closed periods, compared to children who stayed at home. In addition, there was no change in morbidity as the country slowly began to reopen schools.

“When children arrived and they knew they had the disease, we asked them if they knew how they were exposed,” Schlesinger explained. “Only about 10% thought they got it in school.

He pointed out that the children involved in the study were children who came to the emergency room not for COVID but for other reasons, whether it was pneumonia, a broken toe or appendicitis. . In addition, the study represented a representative sample of the population of Jerusalem but does not indicate whether the same would be observed in Tel Aviv or Haifa.