Children are being urged to continue not hugging their grandparents, even if they've been vaccinated.
Dr Jenny Harries, the deputy chief medical officer, said youngsters should remain socially distanced from their grandparents until experts are 'absolutely sure' about the impact of the vaccine rollout.
More than 18 million people across the UK have now received a first dose of a coronavirus vaccine.
And a further 600,000 have been given their second dose.
At a Downing Street press briefing, Dr Harries said: "The testing programme in schools is clearly going to mean that people – parents, grandparents and teachers and other school children – can be very assured schools will be as safe as they can be because we are trying to remove infection from that environment.
“And of course, that will have a really positive impact on breaking chains of transmission in communities and in those families.
“But the slight caveat to that is, having got so far down the line with this and now on the road map, very, very carefully coming out, I would encourage children not to go off yet, even if their grandparents have had their vaccinations.
“Not to go hugging them too much until we’re absolutely sure what the impact of that vaccine rollout has been.
“I’m sure it’s going to be positive but we just need to take a steady course through the road map."
A government advertising campaign launched today has called on people to continue observing stay at home rules, ahead of the planned reopening of society in the coming months.
People are being told to continue wearing a mask, social distancing and washing their hands.
A stay at home order will remain in place in England until at least March 29.
England’s chief medical officer Professor Chris Whitty said: "Infection rates are falling, but they still remain very high and the impact of Covid-19 is still putting pressure on hospitals across the country.
"Vaccines give clear hope for the future, but for now we must all continue to play our part in protecting the NHS and saving lives."
