Strong response detected regardless of the duration between infection and vaccination; multi-ethnic groups show similar response.
Although data from clinical trials are encouraging, there is real evidence regarding the COVID-19 vaccine remains scarce. In particular, response to the vaccine among those previously infected with EARS-CoV-2 is still not fully understood.
Researchers at Bar-Ilan University and the Ziv Medical Center are now reporting preliminary evidence that people previously infected with the virus have reacted very strongly to one dose of Pfizer vaccine, regardless of when they are infected or whether they have detectable antibodies to COVID. 19 het. before receiving the vaccine.
Their study, published on February 11, 2021 in the journal Euro surveillance, was performed on a group of 514 staff members at the Ziv Medical Center. Seventeen of them were infected with COVID-19 between one and ten months before receiving the first dose of vaccine. The antibody levels of the whole group were measured before vaccination and thereafter to determine the response to the vaccine.
The response among those previously infected was so effective that it opened the debate as to whether one dose of the vaccine might be sufficient. “This finding could help countries make informed decisions about vaccine policies – for example, whether those previously infected should be vaccinated, and if so, with how many doses,” says Prof. Michael Edelstein, from the Azrieli Faculty of Medicine of Bar -Ilan University, who led the study. “It also provides the assurance that detecting antibodies after infection does not necessarily mean that protection after infection is lost.”
The research also provided evidence that immune responses in multi-ethnic groups were similar. The Ziv Medical Center, where the study was conducted, is staffed by a workforce consisting of, among others, Jews, Arabs and Druze. Members of each of these groups responded very similarly to the first dose of the vaccine, which is a welcome finding because the virus itself affects some groups more than others.
The good response to one dose of the vaccine among those previously infected, regardless of the duration between infection and vaccination, is good news. However, the researchers emphasize that their findings need to be confirmed in a larger group before drawing definitive conclusions. The researchers continue to follow health professionals after their second dose to better understand how long the vaccine will protect COVID-19 in different groups of people.
Reference: “Impact of age, ethnicity, gender and previous infection status on immunogenicity after a single dose of BNT162b2 mRNA COVID-19 vaccine: actual evidence from health workers, Israel, December 2020 to January 2021” by Kamal Abu Jabal, Hila Ben-Amram , Karine Beiruti, Yunis Batheesh, Christian Sussan, Salman Zarka and Michael Edelstein, 11 February 2021, Euro surveillance.
DOI: 10.2807 / 1560-7917.ES.2021.26.6.2100096