Pfizer says an early peek at its vaccine data suggests the shots may be 90% effective at preventing COVID-19.
Monday's announcement doesn't mean a vaccine is imminent. The interim analysis, from independent data monitors, looked at 94 infections recorded so far in a study that has enrolled nearly 44,000 people.
Pfizer did not provide any more details about those cases, and cautioned the initial protection rate might change by the time the study ends.
The shots are made by Pfizer and its German partner BioNTech. Pfizer has said it plans to seek U.S. review later this month.