Health Secretary Matt Hancock has hailed the vaccination of more than half the UK’s adult population against Covid-19 as a “phenomenal achievement”.
Government data up to March 19 suggests that 26,853,407 people aged 18 and over have now received a first dose of the jab – around 51% of the population.
The Department of Health and Social Care (DHSC) said it remains “on track” to offer the vaccine to all over-50s by April 15.
It comes as countries across Europe have had to impose tougher restrictions amid a rise in Covid-19 cases, with UK scientists warning overseas holidays this summer will be “extremely unlikely”.
Mr Hancock said: “Vaccinating over half of all adults is a phenomenal achievement and is testament to the mammoth efforts of the NHS, GPs, volunteers, local authorities and civil servants in every corner of the UK.
“During April, we will continue to vaccinate those most at risk and around 12 million people will receive their second doses as well.
“It is absolutely crucial people come forward as soon as they are eligible. When you get the call, get the jab, because the more people who are vaccinated the safer we will all be.”
Some 2,132,551 people in the UK – around 4% of all adults – have been given their second dose of the vaccine, while almost 95% of people aged 60 and over have received their first jab, the DHSC said.
Government data suggests that 711,156 vaccines – both first and second doses – were administered across the UK on Friday.
Of those, 636,219 were given in England– the highest daily amount since the NHS vaccination programme began, NHS England said.
Meanwhile, Dr Mike Tildesley, a member of the Spi-M modelling group which advises the Government, said there was a danger that new variants could jeopardise the vaccination programme later in the year.
Other experts have warned there could be a third wave of Covid-19 infections in the UK and advised people not to consider overseas holidays when restrictions ease later this year.
Infectious disease expert Dr Tildesley told BBC Radio 4’s Today programme: “I think that international travel this summer is, for the average holidaymaker, sadly I think, extremely unlikely.
“I think we are running a real risk if we do start to have lots of people going overseas in July and August because of the potential for bringing more of these new variants back into the country.
“What is really dangerous is if we jeopardise our vaccination campaign by having these variants where the vaccines don’t work as effectively spreading more rapidly.”
Government sources said the UK needs to be wary of what is happening in Europe “because in the past that has led to a rise here a few weeks later”, although how things will pan out is uncertain.
European countries are seeing pockets of the South African variant, with studies suggesting vaccines work less well against this variant.
In the UK, hospital admissions and deaths are still coming down due to the effect of vaccines, but there are worries that cases could rise quickly once restrictions are eased.
Professor Andrew Hayward, a member of the Scientific Advisory Group for Emergencies (Sage), said while another wave was “likely” in the UK, the impact could be less deadly than previous ones.
He told Times Radio: “I think another wave is possible. Likely, even.
“I guess the difference is that another wave will cause substantially fewer deaths and hospitalisations because of high levels of vaccination across the sorts of people who would have ended up in hospital or unfortunately dying if they haven’t been vaccinated.
“So the consequences of another wave are less. I think the challenge is of course we don’t know exactly how much less.”
Experts believe there will be an increasing “disconnect” between cases and hospital admissions and deaths going forward, as vaccines work to keep people from dying.
Regarding foreign holidays this summer, Government scientists say it is still unclear what will happen, but the risk of importing cases and variants comes from countries with a higher prevalence than the UK.
In Europe, the French government announced that new lockdown restrictions would be imposed on Paris from midnight on Friday due to an increase in cases.
Chancellor Angela Merkel said Germany may need to apply an “emergency break” on relaxing restrictions amid a rise in infections.
Poland begins a new three-week lockdown on Saturday, with shops, hotels, cultural and sporting facilities closed.
Countries including France, Germany and Italy have begun restarting their vaccine programmes with the AstraZeneca jab – reversing earlier decisions to suspend them over blood clot concerns.
The rollout of the AstraZeneca coronavirus vaccine will resume in Ireland on Saturday, the Health Service Executive announced.
On Friday, Boris Johnson gave a double thumbs-up to mark his vaccination as he was given the jab at Westminster Bridge Vaccination Centre at St Thomas’ Hospital in central London shortly after 6.30pm.