Pharmacists must throw away any extra amount of the vaccine if it does not consist of the 0.3 mL needed for a full dose, Pfizer said. The remaining amount „must never“ be combined with the vaccine from another vial.

The Pfizer vaccine, green-lighted by the FDA on Dec. 11, was developed in less than a year, a fraction of the time it would usually take as researchers worldwide frantically sought an antidote to a virus discovered in China in December 2019.