Children in the UK aged 12 to 15 are set to be able to get a Covid jab, following advice from the UK's chief medical officers.
They have recommended the youngsters should be offered one dose of the Pfizer vaccine.
Some other countries have been vaccinating younger teenagers for some time - but approaches do differ.
What's happening in Europe?
In May, the European Medicines Agency (EMA) approved the Pfizer vaccine for 12 to 15-year-olds. Since then, different EU countries have moved at different speeds.
Denmark (12 to 15-year-olds) and Spain (12 to 19-year-olds) have both now vaccinated most of their child population with at least a single dose.
France too has been moving quickly with 66% of those aged 12 to 17 now single jabbed, and 52% fully vaccinated. By October the country's health pass - or pass Sanitaire - will be extended to under-18s, meaning all teenagers will need to show proof of vaccination or a negative Covid test to access places like cinemas, museums, restaurants and indoor shopping centres.
In June Germany's scientific advisers recommended the vaccine should only be offered to children aged 12 to 15 with underlying health conditions. But in August, after the Delta variant started spreading more widely, the rollout was extended to all those over 12 years old.
In Sweden children aged 12 to 15 are only eligible for a vaccine if they have lung disease, severe asthma or another high-risk medical condition. In Norway, not part of the EU, the vaccine rollout was recently extended to children aged 12 to 15, but only a first dose will be offered, with a decision on a second dose to be made later.
The US - some mandatory vaccination
In May, US and Canadian regulators were the first to approve the Pfizer jab for use in children from 12 years and older. The rollout started immediately at sites across the US with two injections given three weeks apart.
By the end of July, 42% of 12 to 17-year-olds had received their first dose and 32% their second dose of either the Pfizer or Moderna shots.
The drive to vaccinate children came as the US started to battle a rise in infections driven by the Delta variant.