OKLAHOMA CITY - Hundreds of children may have to be revaccinated after a clinic mistakenly stored vaccines at the wrong temperature.

Haley Norman thought her two-year-old daughter, Serenity, was safe from measles, mumps, rubella, polio and hepatitis-A.  After all, Serenity had been vaccinated 10-months ago.  But it turns out, that vaccine may not be good. The Oklahoma City Clinic in Midwest City stored it at the wrong temperature. 

"We were very upset. Trust me. Me and her dad.” Norman said, “Because we had her around newborns."

The clinic won't say how long the vaccines have been stored improperly or exactly how many children are impacted, but told News 9 the number is in the hundreds.

"We noticed the temperatures were out of range. And an out of range temperature can cause a vaccine to actually become inactive,” explained Oklahoma City Clinic CEO Scott Potter. “So, once we noticed that, we immediately took steps to correct it."

The clinic installed high-tech refrigerators to keep the vaccines at the right temperature. If the temperature falls, staffers will automatically be notified on their phones.

"We wanted to make sure that equipment failure wouldn't again potentially in the future lead us to have the kind of difficulties that we've had,” said Potter.

The clinic is also sending out letters to parents, offering to revaccinate children, no charge.

"We're very very sorry that this happened and we know that this is an inconvenience to our patients, and ultimately what we want is to provide fantastic healthcare,” said Potter.

Norman said, apology not accepted. She plans to take Serenity in for a blood test to see if the vaccinations worked. If not, she’ll go elsewhere to have her daughter revaccinated.

"No, we've already switched to OU.” Norman said, “We're done with that clinic, so I'm definitely not going back there."

There is no physical danger to having a child vaccinated twice. The clinic is only sending letters to parents of children who were affected.  So, the clinic said, if you get this letter, follow the instructions to a tee. If you don't receive a letter, the clinic said you have nothing to worry about.