Pfizer and Moderna vaccines are powerfully effective against the virus, a C.D.C. analysis confirmed.
The Pfizer-BioNTech and Moderna coronavirus vaccines are 94 percent effective at preventing symptomatic Covid-19 illness, according to a new study of more than 1,800 health care workers in the United States. The research, which the Centers for Disease Control and Prevention released on Friday, provides yet more evidence that the vaccines are working well even…