SAN FRANCISCO (CBS SF) — Fourteen children were given the wrong dosage of the COVID-19 vaccine at Sutter Health’s Antioch pediatric clinic over the weekend, the health system confirmed Tuesday.

In a statement, Dr. Jimmy Hu, Chair of the Sutter Health COVID-19 Vaccine Task Force, said the parents of the children and federal officials at the Centers for Disease Control and Prevention have been contacted.

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“This weekend 14 patients at our Antioch pediatric vaccine clinic received vaccines with an incorrect amount of diluent,” Hu statement read. “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.”

Hu said the children could suffer from adverse effects of the dosage.

“According to the CDC, patients who receive vaccine with an incorrect diluent volume may experience more arm soreness, fatigue, headache, or a fever in response to the dose given,” he said.

Health officials say that children ages 5 to 11 should receive a third of the dose given to teens and adults. That’s 10 micrograms per shot for youngsters, compared to 30 micrograms per shot for everyone 12 and older. Like everybody else, the younger kids will get two shots, three weeks apart.

“The children received more than the 5-11 year old dose (10 micrograms) and approximately 2/3rds the dose of what a 12 year old or older would get (30 micrograms),” Sutter officials said.

UCSF infectious disease expert Dr. Monica Gandhi said she’s telling parents to not let the mishap deter them from getting their kids vaccinated.

“You know, I think it’s great for you and others in the media to talk about it, because human error does happen,” said Dr. Gandhi. “It’s important to make these stories and explain to people so that everybody who is handling these vaccines is careful and thinks about ways to eliminate human error.”

Gandhi said did not anticipate the children who received the incorrect dosage would face any health issues.

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“In terms of these particular kids, if they got 20 micrograms instead of 10, I doubt that there’s going to be any long-term effects.”

Brett Rafighi said he heard about the mix up at Sutter’s weekend pediatric clinic, but it didn’t deter him from visiting the county’s clinic with his child Tuesday.

“Didn’t stop me,” Rafighi said Tuesday. “I’d rather have them be safe if they were somewhere in a crossfire or something, and they were not vaccinated.”

“The vaccine comes as a kind of powder,” explained Gandhi. “Then you put normal saline in there, you dilute it, and it can sit for 10 weeks in the fridge. It looks like they diluted it with too little saline, so that they gave twice the dose to a couple of children.”

It was a mixing error at Sutter. The result was a stronger dose, but not even a full adult dose. In fact, it was probably about what Pfizer initially planned to give children.

“The Pfizer vaccine was already studied at 20 micrograms, at one point, for this age group,” Gandhi said. “It really is a very safe dose. They settled on 10. I’m sure there’s no harm to the children. It’s just a reminder for us and healthcare to be careful. The vaccines are really safe. This dose is just fine. Pfizer could’ve gone with this dose for kids. The vaccines are really effective. We want to get our kids vaccinated. Don’t worry that this is a widespread problem. It’s not.”

Last week, California Health and Human Services Secretary Dr. Mark Ghaly said that more than 110,000 Californians ages 5 to 11 had received their first coronavirus shot — 9% of kids that age in the state.

“We are starting to see this pick up and I’m really encouraged about what this means for our state,” Ghaly said.

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Wilson Walker contributed to this story.