Pfizer Vaccine 97% Effective Against Symptomatic COVID-19, Study Shows

Pfizer-BioNtech's coronavirus vaccine offers more protection than earlier thought, with effectiveness in preventing symptomatic disease reaching 97%, according to real-world evidence published Thursday by the pharma companies.

Using data from January 17 to March 6 from Israel's national vaccination campaign, Pfizer-BioNtech found that prevention against asymptomatic disease also reached 94 percent.

"We are extremely encouraged that the real-world effectiveness data coming from Israel are confirming the high efficacy demonstrated in our Phase 3 clinical trial and showing the significant impact of the vaccine in preventing severe disease and deaths due to COVID-19," said Luis Jodar, Ph.D., senior vice president and chief medical officer of Pfizer Vaccines. 

An earlier real-world study had showed effectiveness at preventing symptomatic disease at 94% and asymptomatic illness at 92%. That study said "the efficacy of the vaccine is preserved in every age group," particularly a week after the second dose of the vaccine.

The new study comes on the one-year anniversary of the World Health Organization declaring COVID-19 a global pandemic. President Joe Biden will deliver his first prime-time address to the nation Thursday night on the state of the nation's fight against the virus as the U.S. nears the milestone of administering 100 million vaccines.

More than 525,000 Americans have died due to COVID-19 since the pandemic began, and over 2.6 million people have died worldwide, according to Johns Hopkins University.