About 45% of Arizonans have had at least one dose of a COVID-19 vaccine. But demand for the shot has slowed — that means more doses are going to waste.

Each of the approved vaccines has different storage requirements. The Pfizer vaccine, for example, has six doses in a vial which have to be administered within hours once the vial is opened, or they’ll be unusable. In the early days of the vaccine rollout, when vaccines were in extremely short supply, that meant providers might scramble to find people to vaccinate at the end of the day to avoid wasting doses.

But supply in the U.S. now exceeds demand and Arizona’s health department director, Dr. Cara Christ said priorities have changed.

“Now we'd like to minimize wastage but not at the expense of getting somebody who is present in your office in front of you vaccinated," Christ said in a call with reporters Friday. “While we do want to minimize vaccine wastage, getting people vaccinated and preventing hospitalization and death is very important."

The Centers for Disease Control and Prevention still encourages providers to use waitlists and appointment systems to use vaccines as efficiently as possible. But instead of telling providers to avoid wasting even a single shot, the latest guidance from the CDC advises providers to avoid wasting the opportunity to vaccinate even just one person — even if that means opening a new vial and letting some doses go unused.

→ Q&AZ: What You Need To Know About Getting The Coronavirus Vaccine In Arizona