It remains crucial that the in-school programme is rolled out as quickly as possible but only 15 councils have vaccinated at least a quarter of 12 to 15-year-olds
Unions are calling for school-age teens to be allowed to use walk-in vaccination centres as in some areas a few as 5% are jabbed.
Take up in England is below 10% in just over a third of the main local authorities and only 15 councils have vaccinated at least a quarter of 12 to 15-year-olds.
By contrast in Scotland – where children can use walk-in centres – take-up is already over 50% in half of local authority areas.
James Bowen, policy director at school leaders’ union NAHT, said: “It remains crucial that the in-school programme is rolled out as quickly as possible.
“We know that the health teams working in schools are working tirelessly to achieve this, but they need full support from the Government.
“Those who want to get the vaccination should be able to do so as quickly as possible.
“Allowing 12-15 year olds to attend walk-in vaccination centres would be a sensible decision.”
Do you agree? Have your say in the comment section
Three million pupils aged between 12 and 15 across the UK are eligible to receive a first dose of the Covid-19 vaccine as part of a rollout that began a month ago.
In England, jabs are being carried out in schools by nurses and immunisation teams.
In Scotland doses can be received by attending drop-in vaccination centres at GP clinics, pharmacies and community centres.
Around one in 10 children in England in school years seven to 11 were likely to have tested positive for Covid-19 in the week to October 9 – the highest rate for any age group – according to the Office for National Statistics.
Get the latest news you want direct to your inbox. Sign up to one of the Mirror’s newsletters
Geoff Barton, general secretary of the Association of School and College Leaders (ASCL), said: “We are hearing reports from around the country of very varied delivery of the Covid-19 vaccine to 12 to 15-year-olds in schools and significant delays to the vaccination programme, which the Government had originally hoped to complete by half-term.
“Schools have reported logistical problems such as the vaccination teams having insufficient staff to deal with the number of students needing jabs, running out of vaccines or even not turning up when they have arranged to.
“The Government needs to do everything possible to boost the delivery and take-up of the vaccination.”
The Prime Minister’s official spokesman said: “There are a number of different factors, there’s no one single issue that presents a challenge.
“As ever with Covid there are a number of challenges to overcome.”
Another potential Covid-19 vaccine has recorded positive trial results but it comes after Britain cancelled its order for doses.
Pharmaceutical firm Valneva had set up a manufacturing plant in Livingstone, Scotland, and announced its jab showed stronger antibody responses than the AstraZeneca jab.
It is hoped the vaccine will trigger a stronger T-cell response that is a more robust defence against new variants.
The phase three trial had recruited 4,012 people across 26 trial sites in the UK.
Lead trial investigator Prof Adam Finn, of Bristol University, who also sits on the JCVI, said: “The low levels of reactogenicity and high functional antibody responses alongside broad T-cell responses seen with this adjuvanted inactivated whole virus vaccine are both impressive and extremely encouraging.
“This is a much more traditional approach to vaccine manufacture than the vaccines so far deployed in the UK, Europe and North America and these results suggest this vaccine candidate is on track to play an important role in overcoming the pandemic.”
The UK deal with the French company for 100 million doses was scrapped last month as Health Secretary Sajid Javid told MPs it had been “clear” the vaccine “would not get approval” here.
Prof Finn said Mr Javid’s comments had been “corrected in Hansard” and suggested they were incorrect.
Valneva’s chief medical officer Dr Juan Carlos Jaramillo told a briefing they expected to get UK approval around the turn of the year.