Covid-19 cases will surge as children in England return to school this week, Downing Street has warned - but there is still no plan to vaccinate 12 to 15-year-olds.
Boris Johnson's spokesperson told reporters that the consensus among experts is that coronavirus infections will increase after the end of the summer holidays, just as they did in Scotland.
Asked whether a surge in cases was inevitable, the spokesman said: "I’m not a modeller or an epidemiological expert but I think it’s fair to say that the consensus is that there may be an increase due to the return of schools. “We’ve seen cases rise in Scotland for example so we will need to monitor that carefully.”
Scotland recorded its highest ever number of daily coronavirus cases two weeks after schools reopened following the summer holidays, with First Minister Nicola Sturgeon saying the "sharp" rise is likely down to students being back in the classroom.
Mr Johnson's spokesman insisted disruption to education will be kept to a minimum because of high vaccine rates among teachers and daily mass Covid testing for students.
Ministers have been criticised by education unions for not offering Covid jabs to 12 to 15-year-olds during the summer holidays, but recent guidance from the government's vaccine advisers means most will not be immunised as they return to the classroom.
The independent Joint Committee on Vaccination and Immunisation (JCVI) last week refused to give its approval to vaccinate that age group, saying the health benefits only marginally outweigh the risks of rare potential negative side effects.
It said the government should seek further advice from the UK's four chief medical officers (CMOs) before deciding if health 12 to 15-year-olds should be offered a jab.
The only people in that age group currently allowed Covid vaccines are those with severely weakened immune systems.
Ministers had reportedly been growing impatient over the lack of progress in vaccinating younger age groups, but the prime minister's spokesperson said the government trusts the advice of its independent advisers.
Work is already underway on assessing the impacts of vaccinating 12 to 15 year olds, Mr Johnson's spokesman said, and the NHS will be ready to rollout jabs in schools as soon as a decision is made.
Number 10 said it expects England's Chief Medical Officer Chris Whitty wants to "provide certainty" on the issue will provide an update "as soon as possible".
While the Moderna and Pfizer/BioNTech vaccines have already approved as safe for use in 12 to 17-year-olds, the risk to children involved a very rare side effect known as myocarditis [inflammation of the heart muscle].
It said CMOs should investigate the wider impacts of vaccinating that age group before making a decision, given that healthy young people are very unlikely to become severely ill from Covid.
Schools in England no longer have to keep pupils in year group "bubbles" to reduce mixing and face coverings are no longer advised.
Can children defy their parents if jabs are rolled out to under-16s?
Children do not have to isolate if they come into contact with a positive case of Covid-19. Instead, they will need to get a PCR test and isolate only if positive.
But all secondary school and college pupils are being invited to take two lateral flow tests at school, three to five days apart, in England on their return.
Schools and colleges are being encouraged to maintain increased hygiene and ventilation, and secondary school and college pupils in England have been asked to continue to test twice weekly at home.
Parental consent will be required before 12 to 15 year olds are vaccinated against coronavirus, the government has said.