By Stephanie Stahl

PHILADELPHIA (CBS) — There is a new warning from the U.S. Food and Drug Administration about some coronavirus vaccines due to a rare possible side effect. Health officials say two of the vaccines can cause heart inflammation, but they say the benefits of the vaccines still far outweigh these very minor risks.

The FDA is putting a new warning on the Pfizer and Moderna vaccines.

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Researchers at the U.S. Centers for Disease Control and Prevention found a likely connection between the shots in teens and young adults and myocarditis, a rare type of heart inflammation.

Dr. Paul Offit is with the Children’s Hospital of Philadelphia.

“This is a short-lived temporary phenomenon,” Offit said.

The CDC investigated more than 1,200 cases, most linked to the Pfizer vaccine that occurred after the second dose and were mainly in males 24 or younger.

Symptoms include chest pains, heart palpitations and shortness of breath.

“I woke up at 2 a.m. with chest pain,” 16-year-old Noah Hiers said.

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Noah was rushed to the hospital just two days after he received his second dose.

“This experience was much better than getting COVID and much lower risk of anything long-lasting occurring,” Noah said.

The CDC report says the benefits of the vaccines “still clearly outweigh the risks.”

“We have over 300 deaths in children from this virus,” Offit said. “A choice to not get a vaccine is not just a choice to put those children at risk. it’s a choice to put everyone they come in contact with at risk. We need a vaccine to get on top of this pandemic.”

Health experts say the vaccine is especially important now with the more contagious Delta variant quickly spreading.

“The more we allow this virus to continue to spread the more it’s going to create these different variants that are more contagious, the higher the percentage of the population we’re going to need to vaccinate,” Offit said.

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Most cases of COVID-19 are now happening in people who are not vaccinated and the virus can also cause heart problems, along with many other complications.

Stephanie Stahl