The FDA has approved Pfizer and BioNTech’s single-dose 0.3 mL vial version of its COVID-19 vaccine Comirnaty for individuals 12 years and older.

The vaccine was previously only available in multiple dose vials, which presented some challenges for administering doses and leading to some wastage.

The multiple-dose vials come in two versions, one with a grey cap that contains 1.8 mL vaccine that must not be diluted and another with a purple cap that contains 0.45 mL that must be diluted before administering the vaccine.