Experts determining if kids will need different doses of COVID-19 vaccines

Posted at 2:48 PM, Jan 29, 2021

Pfizer just recently wrapped up enrolling participants in its vaccine trials for children and Moderna is about to start enrolling participants between 12 and 17 years old next month.

The two vaccines built a lot of confidence when they were tested in adults. Both have between 94% to 95% efficacy, which is higher than most vaccines.

Pediatric doctors we spoke to say the vaccines are expected to work similarly in children and adolescents, but the question is whether the doses need to be adjusted in younger children.

“It's not the same as drugs where we tend to need by weight. Like if you're a little child, you need certain milligrams per kilogram. Vaccines don't typically work that way,” said Dr. James Campbell at the University of Maryland School of Medicine.

A difference in doses is common, especially among younger children. Take the flu shot, for example. Kids under nine years old need two doses that are one month apart.

Researchers will also look at whether there's a difference in side effects. Doctors say it's likely children will experience the same side effects, but they may not necessarily experience them at the same level as adults.

“If there's fever, especially when you get down to the younger children, if you're having high levels of high fever, some of those kids might be at risk of having what we call febrile seizures, which means shaking fits associated with high fevers,” said Campbell.

This can happen with any type of fever.

The important thing in the trials will be that not too many children get febrile fevers.

Once vaccines are approved for young children, doctors say they will play a key part in herd immunity.

“Children make up a substantial enough portion of the population. And even though it is true, that most children, so far, mostly only experience mild infection from COVID-19, their role in transmission may well be substantial enough that if they are not vaccinated, are still able to be infected,” said Dr. Kristin Moffitt, a physician at Boston Children's Hospital.

Both doctors say while fewer children have experienced severe symptoms and death from COVID-19, the virus has still affected them at higher numbers than other illnesses, which adds to the importance of getting children vaccinated.