In this March 2, 2021, file photo, a pharmacy technician loads a syringe with Pfizer's COVID-19 vaccine at a mass vaccination site at the Portland Expo in Portland. Credit: Robert F. Bukaty / AP

The Sanford Walgreens may have given some Mainers deactivated doses of COVID-19 vaccines.

Walgreens said this only happened at the Sanford location, and that the company has contacted everyone who may be affected.

The company said customers may have received a vaccine dose diluted with sterile water instead of saline, which is used to prepare the shot. This may affect the efficacy of the vaccine.

“We are reaching out to the impacted patients and will administer a COVID-19 vaccination as soon as these patients are available to return to the pharmacy for a corrected first and/or second dose within the appropriate time frame,” Walgreens officials said.

The company said that it is reviewing its procedures so this doesn’t happen again.

The Maine Center for Disease Control and Prevention said there was no health risk from the mistake, which was reported to state authorities.