People vaccinated against the coronavirus rarely become infected, and if they become infected, their viral load is lower and they are less likely to infect other people.
The authors of the new study assessed the decline in the number of new cases of COVID-19 in Israel as the vaccination campaign progresses, Nature Medicine reported.
In Israel, mass vaccination began on December 19, 2020, almost half of the adult population received the first dose of the vaccine produced by Pfizer – BioNTech for 9 weeks. To assess the impact of vaccination on the risk of infection in unvaccinated people, scientists estimated the incidence rates of COVID-19 in 177 communities with varying vaccination coverage rates from December 2020 to March 2021.
They also analyzed data on children under 16 who were not covered by the campaign. Scientists were interested in how the number of positive PCR tests for SARS-CoV-2 changes in different communities at certain intervals.
It turned out that, on average, for every 20% increase in the number of people vaccinated, the number of positive tests decreased by about half.
According to scientists, the results of their study do not take into account the natural immunity against coronavirus in people who have had COVID-19. They believe the observed decline in the number of new cases of the disease among unvaccinated people amid mass vaccinations is good news. In the future, they want to evaluate the possibilities of the vaccination campaign in creating herd immunity.