One COVID-19 Vaccine Dose Provokes Immune Response in Those Previously Infected
Israeli researchers from Bar-Ilan University and Ziv Medical Center reported preliminary evidence that people previously infected with the SARS-CoV-2 coronavirus responded very strongly to one dose of the Pfizer - BioNTech SE vaccine (Comirnaty), regardless of when they were infected and whether or not they had detectable antibodies against COVID-19 before receiving the vaccine.
Their study, published on February 11, 2021, in the journal Eurosurveillance, was conducted on a cohort of 514 staff members at Ziv Medical Center.
"This finding can help countries make informed decisions regarding vaccine policy. For instance, whether those previously infected should be vaccinated in priority and, if so, with how many doses," says Prof. Michael Edelstein, of the Azrieli Faculty of Medicine of Bar-Ilan University, who led the study, in a press statement.
"It also offers reassurance that not having detectable antibodies after being infected does not necessarily mean that protection following infection is lost."
These researchers also provided evidence that immune response was similar across multi-ethnic groups.
The Ziv Medical Center, where the study was conducted, is staffed by a workforce comprised of Jews, Arabs, Druze, and others. Members of each of these groups responded very similarly to the first dose of the vaccine, a welcome finding considering that the virus itself is known to affect some groups more than others.
However, the researchers emphasize that their findings should be confirmed in a larger cohort before reaching definitive conclusions.