OAKLAND, Calif. - They're only in elementary school, but 6-year-old Sofia Chavez and her 9-year-old brother Nico are already helping to make history.
Since June, the children have been part of Pfizer's pediatric COVID-19 vaccine trial at Stanford for children ages 5 to 11-years-old.
"I'm proud of myself for doing it because I'm really nervous with shots," said Sofia, who is in the first grade.
"You're going to be part of saving the world," said Nico, a fourth grader, "I think it's pretty cool to be the first kids under twelve to get the vaccine."
Thousands of children have been enrolled in Pfizer's clinical trials to test the safety of the mRNA vaccine.
Renee and Miguel Chavez say researchers made sure their children and others in the study weren't being forced to get the shots.
"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 first shot was in June and the second shot was in July. Parents were not told whether their children were receiving the Pfizer vaccine, or a placebo shot.
Renee and Miguel said they watched their children for any symptoms.
Nico says he felt fatigue and chills but was fine after a few days. Renee is a pediatric ICU nurse and says while some parents might worry about the vaccine and safety, for her, seeing COVID cases at work was a factor in wanting her children to enroll 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.
As children head back to school, there are increasing concerns about transmission among children.
According to the American Academy of Pediatrics, there were 204,000 COVID cases among children in the United States last week. That's up from 38,000 in July. The American Academy of Pediatrics says children account for nearly 15% of all cases. Children represent between 1.6% to 3.6% of hospitalizations across the country.
Many parents are wondering when their children might be able to get a COVID vaccine.
"The clinical trials should be finished by September," said Dr. Yvonne Maldonado, the Stanford Professor of Infectious Diseases who is leading the pediatric clinical trial at Stanford, "The company should be able to provide the data to the FDA by October."
After that, the FDA will review the data for safety to decide whether to issue emergency use authorization.
"With children in particular what we want to look for is immediate reaction to the vaccine like fevers or chills or flu-like symptoms," said Maldonado, "The question will be will they be severe, what percentage of children have them, how long do they last?
Renee says as part of the study they received cell phones to send weekly reports about the children's health.
They also received an at-home covid test in case the children show symptoms.
The Chavez family said they were told they will learn whether they received the vaccine or a placebo in December. Safety monitoring is expected to continue for two years.
"We're going to be tracking short- and long-term safety, we're going to be tracking immune responses, whether children need boosters," said Maldonado.