COVID vaccine mix-up at Aurora Mariano's results in some getting Pfizer shot instead of Moderna

AURORA, Ill. (WLS) -- An investigation is now underway into a major vaccine mix-up at the Aurora Mariano's pharmacy that resulted in eight people getting the Pfizer vaccine for their second dose. They should have gotten Moderna, since that's what they received for their first dose.

ABC7 Eyewitness News spoke off-camera with the family of a Naperville man who was given the wrong second dose. Thankfully, he's doing well, but is concerned a mix-up like this happened in the first place.

In a statement, the grocery chain said: The Mariano's Pharmacy located in Aurora, IL administered a small number of Pfizer Covid-19 vaccines to people who had received the Moderna vaccine at their first appointment. No adverse events for the affected patients have been reported. All impacted patients have been contacted. We thank these patients for their understanding and have apologized for their inconvenience. Kroger Health has reported to both the CDC and the Illinois Department of Public Health, and our team is investigating the matter and will take steps to prevent a similar situation from recurring in the future.

"I don't think there's really an issue of safety here, it's just a matter of knowing how effective it is," said Dr. Zachary Rubin, clinical immunologist.

Rubin said the big unknown and concern is: how much protection can a mix of two vaccines provide?

"While it's the same technology of mRNA vaccine technology, it's not the exact same product," Rubin explained. "There are several things that go into the delivery, the preservatives that are involved."

The CDC has said the two vaccines are NOT interchangeable and the "safety and efficacy of a mixed-product series have not been evaluated. Both doses should be completed with same product. If mixed, do not repeat dose."

Rubin recommends those impacted contact their physicians and suggests testing for any antibody production from the vaccine combination.