A New Jersey family says that their son was hospitalized after he had an adverse reaction to the second dose of the Moderna COVID-19 vaccine.

The Romanienko family says that their son is on the mend, but there were some scary moments for he and his family days after he received the second dose of the vaccine.

Preston Romanienko, 21, was excited and optimistic about getting vaccinated.

“I felt like this was going to be something good that could come out of it,” he says.

Romanienko says that he expected some side effects associated with the second dose, but that the symptoms he had in the days following that dose went beyond what he expected.

“A greater amount of tightness in breath than I felt in the first dose and with that, there were also more heart palpitations than I was experiencing,” he says.

Romanienko’s mother Victoria says that he was expressing pain a day after the shot.

“We thought it was anxiety,” she says.

But by the middle of the week, Romanienko’s symptoms continued, and the family decided to take him to the hospital. Romanienko was hooked up to monitors which said he was OK, until his blood work came back.

“The troponin levels were in the high 600s. It really concerned me…that is known as the heart attack enzyme,” Victoria says.

Romanienko has never had any heart problems. His only underlying condition is asthma. He spent four days in the hospital being tested for a number of illnesses, which all came back negative. Doctors could only conclude his symptoms were caused by the vaccine.

This comes as use of the Johnson & Johnson vaccine is on hold while health officials investigate reports of severe blood clotting in six female patients.

“With any vaccine - live vaccine, dead vaccine, mRNA vaccine- just in general with vaccines, you have to expect some bandwidth of a reaction and there are good reactions, there are typical reactions and then there are about 1 in a million-atypical reaction,” says Dr. Alexander Salerno with Salerno Medical Associates.

Salerno said the Moderna and Pfizer vaccines can't be compared with J&J because the technology is different and what happened to Romanienko is possibly an isolated incident.

Romanienko is expected to be OK. His family says that they hope his experience is a cautionary tale for others.

“We want to make sure when these kinds of reports come in, especially as more and more younger adults are going to be having these vaccines,” says Victoria. “That they're aware that this could be something for someone with a really high immunity, such as our youth, that this might be one of those possible reactions.”

Romanienko has a follow-up appointment with his doctor. He says that he also plans to write to Moderna, the Centers for Disease Control and Prevention and President Joe Biden about his concerns about the vaccines and to consider a halt on other shots until there is more information.