Are COVID Vaccination Programs Working? Scientists Seek First Clues

January 22, 2021

(Nature) – The results from Israel are among the first to report the impact of vaccines administered to people outside clinical trials. They provide an early indication that the two-dose RNA-based vaccine developed by Pfizer–BioNTech can prevent infection or limit its duration in some vaccinated people. In a preliminary analysis of 200,000 people older than 60 who received the vaccine, compared with a matched group of 200,000 who did not, researchers found that the chances of testing positive for the virus were 33% lower two weeks after the first injection.