Researchers from Bar-Ilan University and Ziv Medical Center have presented preliminary evidence that people previously infected with coronavirus responded positively and strongly to one dose of the Pfizer vaccine, regardless of when they were infected and whether or not they had detectable antibodies before inoculation. .
The study was conducted among a group of 514 employees of the Ziv Medical Center in Safed, 17 of whom were infected with COVID-19 between one and 10 months before receiving the first dose of the vaccine.
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A member of the medical staff who receives the coronavirus vaccine at the Sheba Medical Center near Tel Aviv
Photo: Yariv Katz
The group’s antibody levels were measured before and after receiving the injection to determine the response to the vaccine.
The response among those previously infected was so effective that it opens the debate as to whether one dose of the vaccine may be sufficient in certain situations.
“This finding can help countries make informed decisions about vaccine policy – for example, whether previously infected individuals should be vaccinated as a priority and, if so, by how many doses,” said Prof Michael Edelstein of the Bar’s Faculty of Medicine. Ilan University. who led the study.
“It also provides assurance that the lack of detectable antibodies after infection does not necessarily mean that protection is lost after infection,” he says.
However, the researchers stressed that their findings need to be confirmed in a larger cohort before drawing definitive conclusions.
The researchers will continue to follow health professionals after their second dose to better understand how long the vaccine will protect people against COVID-19 in different groups.
France recommended on Friday that people who have already recovered from Covid-19 receive a single dose of vaccine, making it the first country to issue such guidelines.