Parents say Walgreens mistakenly injected them and their two kids with the Covid-19 vaccine instead of flu shot - CNN

"All I could say to them was, 'What does this mean for my kids?'"

Although Alexandra and Joshua, already fully vaccinated since last April, were concerned for themselves, they were more worried about Sophia, 5 and Lukas, 4.

"Lukas started feeling sick before we even got home from Walgreens," Alexandra said.

"There is a lot of data out there now in 5-year-olds and older."

He added that Alexandra and Joshua's extra dose of the vaccine is similar to receiving a booster shot.

"The 4- and 5-year-old are also under treatment of a pediatric cardiologist for tachycardia and elevated blood pressure, respectively."

After a follow-up appointment Tuesday, Alexandra said that Lucas has improved but Sophia has worsened.

Those symptoms include high blood pressure, fevers, chest pain, and headaches.

"It's been well over a week and I still have high blood pressure and chest pain," Joshua said.

He said that he is being monitored by his doctor for the blood pressure and chest pains.