Quirks and Quarks

An inside scoop on how COVID vaccines are being tested on kids

An investigator on Pfizer’s vaccine trials explains how they came to the conclusion that the vaccine is safe and effective in children, and why it’s important that kids get the shot, even though they don’t get as sick with COVID-19 as adults do.

Kids showed almost twice the immune response to Pfizer-BioNTech's vaccine compared to adults, says researcher

Vaccine eligibility may soon open up for kids aged 5 to 11. (Ben Garver/The Berkshire Eagle via AP)

September is back-to-school time, but this year, the return to school was more stressful than usual for some, thanks to the ever-present pandemic and the risk that classrooms would be culturing COVID-19.

Vaccines have helped control the spread of the disease in adults, and children 12 and up. But many have been waiting for younger kids to get access to the same protection — especially as pediatric cases rise with the more contagious Delta variant.

Earlier this week, that door started to open, as Pfizer-BioNTech announced that clinical trials showed its vaccine produced a robust immune response in children aged 5 - 11. Scientists and regulatory agencies still have to carefully review the results of those trials, but it's a big step toward approving these vaccines for widespread use in younger kids.

"Kids have a really great immune system and so respond well to vaccines," said Dr. Kawsar Talaat, an investigator on Pfizer's vaccine trials.

A Toronto kindergarten student on her first day of class in Sept. 2020. (Evan Mitsui/CBC)

Vaccine trials are typically first done in healthy adults to prove safety and efficacy, and then the researchers move into other demographics. In each age group, they look for potential side effects, and then measure the immunity levels generated by the vaccine.

"12 to 15 year olds had almost twice as good of an immune response as the next age group, 16 to 25, and even a much higher antibody response than adults 18 to 50 or over 65," Dr. Talaat told Quirks & Quarks host Bob McDonald. "Kids five to 11 had the same immune response as the adolescents, so you expect it to be incredibly effective in that population."

Dr. Talaat is an infectious-disease physician and vaccine scientist at the Johns Hopkins Bloomberg School of Public Health. She said that even though kids tend not to get sick from COVID as frequently or seriously compared to adults, getting this age group vaccinated is crucial in slowing down the pandemic's spread.

"There is absolutely a benefit to protecting the kids. There's also a benefit to society as a whole, because the more people you vaccinate, the less susceptible people the virus will find to replicate in and transmit to other people, and the better control you can get over the pandemic."

You can listen to Bob McDonald's full conversation with Dr. Talaat at the link above.


Produced and written by Amanda Buckiewicz