Pfizer Inc and its German partner BioNTech SE have begun testing their COVID-19 vaccine in children under age 12.
On Wednesday, Pfizer spokesperson Sharon Castillo said the first volunteers in the early-stage trial were given their first injections.
The vaccine was authorized by the U.S. Food and Drug Administration (FDA) in late December for those aged 16 and older.
The companies hope they will be able to expand vaccination to that age range by early 2022.
Pfizer Inc and BioNTech has begin testing their coronavirus vaccine in children between ages six month and 12 (file image)
The pediatric trial, which will include children as young as six months old, follows a similar one launched by Moderna Inc last week.
The safety of their two-shot vaccine at three different dosages – 10, 20 and 30 micrograms – in a 144-participant trial.
Researchers plan to later expand to a 4,500-participant late-stage trial with, children will be split into three groups: ages six months to two years, ages two to five years and ages five to 12.
In each group, about half will receive the two doses 21 days apart and the other half will be given the placebo.
The team will test the safety, tolerability and immune response generated by the vaccine, likely by measuring antibody levels in the young subjects.
Provided the vaccine is proven to be safe and effective, the trial will be unblinded at the six-month follow-up, meaning those who received the placebo will be offered the vaccine.
Castillo said the companies hope to have data from the trial in the second half of 2021.
Meanwhile, Pfizer has been testing the vaccine in children from age 12 to 15. The company expects to have data from that trial in the coming weeks, she added.
Only the Pfizer-BioNTech vaccine is being used in 16- and 17-year-olds in the U.S.
Moderna’s shot as well as Johnson & Johnson’s were cleared for those age 18 and older, and no COVID-19 vaccine has been authorized in younger kids yet.
Nearly 66 million doses of the vaccine had been administered in the United States as of Wednesday morning, according to data from the CDC.
Children are often the last group to be tested during clinical trials because they are not merely little adults.
Their bodies and immune systems behave differently, meaning they might have different treatment needs.
What’s more, children may need different doses or needle sizes depending on their height, weight and age – which is why most children are only vaccinated after safety has been well-documented in the adult population.