The United States has given full approval to Pfizer’s Covid-19 vaccine, a milestone that could lift public confidence in the shots and spur more companies, universities and local governments to make vaccinations mandatory.

The formula made by Pfizer and its German partner BioNTech now carries the strongest endorsement from the Food and Drug Administration, which has never before had so much evidence to judge a shot’s safety.

“The public can be very confident that this vaccine meets the high standards for safety, effectiveness and manufacturing quality the FDA requires of an approved product,” acting FDA Commissioner Janet Woodcock said in announcing full approval, which comes as the US battles the most contagious coronavirus mutant yet, the Delta variant.