Siblings Sofia Chavez, 6, and Nico, 9, might still be in elementary school but are already taking part in making history.

The children, since June, have been participating in Pfizer’s pediatric COVID-19 vaccine trial at Stanford for 1 to 11-years-old children.

“I’m proud of myself for doing it because I’m really nervous with shots,” the first-grader, Sofia, said.

“You’re going to be part of saving the world,” her brother, now in fourth grade, exclaimed, “I think it’s pretty cool to be the first kids under twelve to get the vaccine.”

They are among the thousands of kids signed up for the vaccine’s clinical trials to determine the mRNA vaccine’s safety.

Their parents Renee and Miguel said that the researchers have secured the kids’ permission before getting the trial jabs.

“They made sure they were okay with it and throughout the whole process they would ask if they were comfortable,” said Miguel.

“They had to sign a consent form…that they wanted to participate,” said Renee.

The children received their first shot in June and the second in the following months. Researchers did not inform the parents whether a Pfizer vaccine or placebo shot was given to their children.

The parents said they look out for any symptoms their children might manifest.

Nico experienced fatigue and chills but the side effects subsided not too long.

While some parents might sound concerned over vaccinating their children, seeing the COVID cases in the hospital where she works as a pediatric ICU nurse, Renee remains firm of her children’s participation in the trial.

“The alternative is the possibility of COVID which is more unknown. We don’t know what the long-term effects are in kids,” said Renee.

Stanford Professor of Infectious Diseases Dr. Yvonne Maldonado, who also leads the pediatric clinical trial at Stanford, said the trials are set to be completed this month.

“The company should be able to provide the data to the FDA by October,” the professor said, as reported by KTVU.

“With children in particular what we want to look for is immediate reaction to the vaccine like fevers or chills or flu-like symptoms,” Maldonado added, “The question will be will they be severe, what percentage of children have them, how long do they last?”