ANTIOCH, Calif. (KRON) – Several children in Northern California were administered the wrong dose of the COVID-19 vaccine over the weekend, a healthcare provider with Sutter Health medical centers confirmed.

“14 patients at our Antioch pediatric vaccine clinic received vaccines with an incorrect amount of diluent. As soon as we learned of this, we contacted the parents and advised them of CDC guidance in this situation. The safety of our patients is our top priority, and we immediately reviewed our processes to help make sure this doesn’t happen again,” said Dr. Jimmy Hu, Chair of the Sutter Health COVID-19 Vaccine Task Force.

Patients who receive an incorrect diluent volume may experience more arm soreness, fatigue, headache, or a fever, Hu added, citing the CDC.

Sutter Health refused to clarify whether the children were given extra diluent or less diluent. However, UCSF infectious disease expert Dr. Peter Chin-Hong said the kids affected by this mistake should be just fine.

“I definitely understand the anxiety and fear of parents, but luckily in this case there is some data in using the higher doses in kids in the original trials,” he said, explaining that during Pfizer’s studies, some kids did receive a higher dose and there were no serious side effects reported.

He also put the incident of 14 kids in perspective, saying that one million kids have been given the vaccine in the last week alone. A diluent is a normal, preservative-free saline (0.9% sodium chloride) that is mixed with the vaccine.

It comes in a separate vial from the vaccine, and medical officials are supposed to prepare each dose with a new vial of diluent and a new vial of vaccine every time, according to the CDC’s Pfizer vaccine preparation guide.

For kids ages 5-11 years old, the vaccine is supposed to include 1.3 mL of diluent, according to the CDC. This age group’s diluent dose comes with an orange cap to differentiate from the diluents for those 12 years and up.

If a child was given less diluent, the dose should not be repeated, and their parents or guardians should be made aware of potential side effects. If the child was given extra diluent, then the vaccine administrator should repeat the dose immediately, according to the CDC.