PORTSMOUTH, Va. (WAVY) — Every morning, the 10 On Your Side team is bringing you answers to your COVID-19 vaccine questions. 

WAVY-TV 10 viewer Robert emailed us from the western Tidewater area, curious about why a friend of his got a “leftover” vaccine from his doctor’s office, even though he hadn’t scheduled an appointment.

In our investigation earlier this month, health departments say they are quickly using as much vaccine as they get.

You may hear about “leftover” doses because of the way the Moderna and Pfizer vaccines are shipped and administered.

The vaccine is not preloaded into syringes, like you typically see with the flu shot.

Instead, according to the manufacturers, it comes in a vial that has to be thawed, diluted and then loaded into syringes.

Each vial has 6 to 10 doses, so health department representatives say staff on site try to only open as many vials as they’ll use for appointments scheduled that day. 

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If someone cancels or doesn’t show up, however, the entire vial needs to be used right away, or it will expire and go to waste.

Local health department representatives say they have a system in place for administering those extra doses, and that people should not show up at clinics to see if they can get one.