ATLANTA (Reuters) — The Pfizer Inc/BioNTech SE COVID-19 vaccine was 93% effective at preventing hospitalizations among those aged 12 to 18, according to an analysis released by the Centers for Disease Control and Prevention (CDC) on Tuesday.

The study was conducted between June and September when the extremely contagious Delta variant of the coronavirus was predominant.

Yet, the data from 19 pediatric hospitals showed that among the 179 patients who were hospitalized for COVID-19, 97% were unvaccinated, providing reassurance of the vaccine’s efficacy.

Of the roughly 16% of patients hospitalized with severe enough COVID-19 to require life support, none were vaccinated.

The CDC report builds on trials done by the companies in this age group that showed high immune response against the virus, but which were not designed to demonstrate efficacy against hospitalization.

The Pfizer/BioNTech vaccine is authorized for children as young as 12, and the companies are seeking authorization for use in those as young as 5 years of age.

A panel of experts advisers to the U.S. Food and Drug Administration are expected to weigh in on data on young children later this month.

The CDC data “reinforces the importance of vaccination to protect U.S. youths against severe COVID-19,” the study authors said.