The extraordinary figure comes from data compiled from 2,228 adolescents between November 2020 and September 2021. Over the last few months, researchers were able to take a closer look at how the vaccine protected trial participants four months after their second dose.  

The company previously said in March that its vaccine was 100% effective for the 12 to 15-year-old age group. These new results have reinforced that finding, and shown that the vaccine’s effectiveness has remained strong.  

“As the global health community works to increase the number of vaccinated people around the world, these additional data provide further confidence in our vaccine’s safety and effectiveness profile in adolescents,” Pfizer CEO Albert Bourla said in a statement Monday. “This is especially important as we see rates of COVID-19 climbing in this age group in some regions, while vaccine uptake has slowed.”

The Pfizer-BioNTech vaccine has been approved for emergency use authorization among 12 to 15-year olds by the FDA since May. The companies plan on submitting this new longer-term data to get full regulatory approval in the U.S. and across the globe. 

Previous trial data has shown that the Pfizer-BioNTech vaccine is 91% effective among children under the age of 5, and 95% effective in people over 16 years of age.

Peter Marks, director of the FDA’s Center for Biologics Evaluation and Research, emphasized over the summer how important it is to get younger populations vaccinated when Pfizer’s shot was first approved for 12 to 15-year olds. 

“Having a vaccine authorized for a younger population is a critical step in continuing to lessen the immense public health burden caused by the COVID-19 pandemic,” said Marks.