U.S. Health Secretary Alex Azar said if pharmaceutical company Pfizer Inc. submits interim Covid-19 vaccine to health regulators as quickly as expected, the U.S. government anticipates the beginning of vaccinating Americans in December.

Pfizer Inc.’s experimental Covid-19 vaccine was more than 90% effective based on initial trial results, the company said, a major victory in the fight against a pandemic that has killed more than 1 million people and battered the world’s economy.