The Food and Drug Administration approved emergency use authorization for the Pfizer-BioNTech COVID-19 vaccine Friday, kicking off a massive vaccination campaign to begin early next week.

The first doses of the vaccine, deemed safe and effective enough for public use on Thursday by a panel of infectious disease experts, will be shipped out within 24 hours. The first shots could be administered as soon as Monday or Tuesday of next week, according to Health and Human Services Secretary Alex Azar.