By Nadia Kounang, CNN

Mon November 9, 2020

Drugmaker Pfizer said Monday an early look at data from its coronavirus vaccine shows it is more than 90% effective — a much better than expected efficacy if the trend continues.

The so-called interim analysis looked at the first 94 confirmed cases of Covid-19 among the more than 43,000 volunteers who got either two doses of the vaccine or a placebo. It found that fewer than 10% of infections were in participants who had been given the vaccine. More than 90% of the cases were in people who had been given a placebo.

Pfizer said that the vaccine, made with German partner BioNTech, had an efficacy rate higher than 90% at seven days after the second dose, which means protection is achieved 28 days after a person begins vaccination. The vaccine requires two doses. The US Food and Drug Administration has said it would expect at least 50% efficacy from any coronavirus vaccine.

In an interview with CNN Chief Medical Correspondent Dr. Sanjay Gupta on Monday morning, Pfizer CEO Albert Bourla called the Covid-19 vaccine “the greatest medical advance” in the world’s last hundred years.