Letters inviting children aged 12 to 15 to book a Covid jab are now being sent out in Scotland.
Every child in this age group in the UK is now being offered a single vaccination dose.
When, where and how are the vaccinations taking place?
Earlier this month, the UK's chief medical officers recommended a single Pfizer dose for all 12 to 15-year-olds.
The rollout has started in England, Scotland and Wales, and in Northern Ireland the vaccinations are expected to be offered from October.
The settings will vary throughout the UK.
In Scotland, as well as being invited to book an appointment at a clinic, 12 to 15-year-olds can get vaccinated at drop-in centres.
In England and Northern Ireland, the programme is mostly based in schools. And in Wales, vaccination centres are being used, with different arrangements in place between areas.
Is the vaccine compulsory?
No. When the recommendation was made, Prof Chris Whitty, Chief Medical Officer for England, said the vaccination would be an "offer".
He said young people and their parents needed to be supported, and there should be no stigma attached to their choice.
Do parents have to give permission?
Although parental consent is being sought, children under 16 who can prove they understand the risks and benefits can ask for the vaccine - or refuse it - if they disagree with their parents.
This important legal test of whether a child can consent to treatment is known as "Gillick competence". It is named after a famous dispute in which a teenager wanted contraceptive advice without her mother's consent.
In practice it would be extremely unusual for a child under 13 to be judged Gillick competent.
Teenagers aged 16 and 17 don't need parental permission, unless there are exceptional circumstances.
Why are all children aged 12 to 15 getting a jab?
It is hoped the measure will help prevent further disruption to their education.
Prof Whitty said absence from school "has been extraordinarily difficult for children" during the pandemic, particularly in deprived areas.
Vaccinating children should help keep cases down, although it won't stop the spread of Covid in schools.
Evidence suggests a single jab cuts the risk of catching the Delta variant by about 55%. It also reduces the chances of getting very sick or spreading it to someone else.
Will they get a second dose?
The chief medical officers say that a second dose should not be considered before the spring term.
However, 12- to 15-year-olds will have two doses if they're at higher risk, due to:
- Severe neurodisability (which could include cerebral palsy, autism or epilepsy)
- Down's syndrome
- A severely weakened immune system, including some children with cancer
- Profound and multiple learning difficulties
- Chronic heart, lung and liver conditions
Children of the same age who live with people who have a suppressed immune system are also being offered two doses.
All 16 and 17-year-olds will be invited for a second jab at a later date.
What vaccine is used and will younger children be jabbed?
Under-18s are being given the Pfizer-BioNTech vaccine, although the Moderna vaccine has also been authorised for use in children in the UK.
There is no vaccine currently approved for under-12s in the UK.
Is the Covid vaccine safe for children?
No medicine is completely safe and all are a balance of risk and benefit.
But the Pfizer jab wouldn't have been approved for UK use if it wasn't considered safe.
The vaccine has been linked to incredibly rare cases of inflammation of both the heart muscle (myocarditis) and the sac the heart beats inside (pericarditis). This was found to be more common in younger men, and to be more likely after a second dose.
Both Pfizer and Moderna are conducting trials of their vaccines on children as young as six months old.
How many children have died from Covid?
Almost all children and young people are at very low risk from Covid-19.
Data for England suggests about 25 children died from Covid in the first 12 months of the pandemic.
The majority of them also had severe health problems, including complex neurodisabilities.
Only six had no recorded health conditions.
In the year to 31 August 2021, Public Health England statistics suggest there were around 50 deaths among under-19s.
How does the UK compare to other countries?
Many countries are vaccinating children over the age of 12.
- EU countries including France, the Netherlands, Germany and Italy have begun jabbing children
- The US recommends all over-12s be vaccinated
- China aims to have all 12- to 17-year-olds vaccinated by October
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Correction 21 September 2021: An earlier version of this article wrongly implied that the Gillick competence test was named after a case involving a mother and daughter and this line has been amended.