Researchers at Bar-Ilan University and Ziv Medical Center have presented preliminary evidence that people previously infected with coronavirus responded positively and strongly to a single dose of Pfizer vaccine, regardless of when they were infected and whether or not they had antibodies. detectable before being inoculated. .
The study was conducted on a group of 514 staff members at Safiv Ziv Medical Center, 17 of whom were infected with COVID-19 one to 10 months before receiving the first dose of vaccine.
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A member of the medical staff who received the coronavirus vaccine at Sheba Medical Center near Tel Aviv
(Photo: Yariv Katz)
Antibody levels in the group were measured before and after administration of the vaccine to determine the response to the vaccine.
The response from those previously infected has been so effective that it opens the debate on whether a dose of vaccine may be sufficient in certain situations.
“This finding can help countries make informed decisions about vaccination policy – for example, whether those previously infected should be vaccinated as a matter of priority and, if so, how many doses,” says Prof. Michael Edelstein of at the Bar-Ilan University School of Medicine who conducted the study.
It also provides assurance that having no detectable antibodies after infection does not necessarily mean losing protection after infection, he says.
However, the researchers stressed that their findings should be confirmed in a larger cohort before reaching definitive conclusions.
Researchers continue to follow health workers after the second dose to better understand how long it will protect the COVID-19 vaccine in different groups of people.
France on Friday recommended that people who have already recovered from Covid-19 receive a single dose of the vaccine, becoming the first country to issue such guidelines.