Skip to main content

Tip Sheets

Pfizer vaccine efficacy could be a ‘game changer’

Media Contact

Gillian Smith

On Monday, Pfizer and BioNTech SE announced that Phase III data is pointing to 90% efficacy of its COVID-19 vaccine, exceeding expectations that a vaccine might only reduce symptomatic COVID-19 in 60-70% of cases.

Cornell University government professors Douglas Kriner and Sarah Kreps recently published a study in JAMA Network Open showing that if an initial COVID-19 vaccine is about as effective as a flu shot, uptake by the American public may fall far short of the 70% level needed to achieve herd immunity.


Douglas L. Kriner

Professor of Government

Kriner says:

“If confirmed by additional data, our research shows these efficacy levels would play a key role in convincing a skeptical public to take the vaccine.   

 “Our study was specifically designed to determine how much influence vaccine efficacy – and other characteristics including the prevalence of major and minor side effects, protection duration, and political factors – would have on Americans’ willingness to take a COVID-19 vaccine." 

Professor in Cornell University’s Department of Government

Sarah Kreps

Professor of Government

Kreps says: 

"We found considerable public reluctance to take a vaccine that was only 50% effective – the FDA’s minimum efficacy threshold for approval.   

“However, if the vaccine was 90% effective it would significantly increase Americans’ willingness to vaccinate by more than 10%, critical to ensuring enough public acceptance to help the U.S. eventually get closer to herd immunity. Our findings suggest politics will also matter – even in a post-election environment. But a highly effective vaccine exceeding most prior estimates could be a game changer with the public.” 

Cornell University has television, ISDN and dedicated Skype/Google+ Hangout studios available for media interviews.