The EU cleared Pfizer's Covid-19 vaccine for use in children aged five to 11 on Thursday, the first jab to be approved in a cohort where the virus is rapidly spreading.
Only a small handful of countries had previously given the nod for coronavirus vaccinations in younger children, including the United States, Israel and Canada.
"I'm glad to tell you that Comirnaty from today has received approval for children five to 11 years of age," said Marco Cavaleri, head of vaccine strategy at the European Medicines Agency (EMA), using the vaccine's brand name.
"This is based on a different dose in the one used in adults, essentially it's a much lower dose," he told an online public meeting.
The vaccine was already cleared for use in people aged 12 and over in the 27-nation EU.
Children aged five to 11 will be given one third of the dose that older people receive, with two injections, three weeks apart, the EMA said in a statement.
The vaccine was 90.7 percent effective in a study of nearly 2,000 children of that age, it added.
Side effects were usually "mild or moderate" lasting a few days, and included pain in the injection site, tiredness, headache, muscle pain and chills.