Everyone aged 44 and above in Britain will now be able to book their COVID-19 jab starting on Monday as the UK's National Health Service (NHS) vaccine programme expands further to more younger age groups.

Around half a million 44-year-olds will receive a text message inviting them to get their jab through the National Booking Service, with England's top doctor urging people to come forward for their jab when they are invited.

The move to the next age cohort in the vaccination programme comes alongside the latest NHS figures showing that more than two-thirds of people aged 45 to 49 have now been vaccinated as the programme moves through age and risk-based cohorts.

"Now that 95 per cent of all over 50s have had their first jab, and more than two-thirds of those aged 45-49, we are opening up vaccinations to 44-year olds," said UK Health Secretary Matt Hancock.

'The biggest vaccination programme in NHS history has delivered 45.5 million doses so far across the UK, and we are on track to offer a jab to all adults by the end of July. I encourage everyone who is 44 to book an appointment to get the jab it will protect you and your loved ones, and help put this pandemic behind us,' he said.

The NHS said the decision to move to the next group of people aged between 40 and 43 will be set out in the coming days with the NHS vaccinating in line with Joint Committee on Vaccination and Immunisation (JCVI) advice and as supply allows.

"Thanks to NHS staff, people aged 45-49 have been hot on the heels of millions of people most at risk who were quick to take up the offer of a vaccine with more than two thirds getting their lifesaving jab, marking another medically important milestone in the biggest vaccination campaign in NHS history," said Sir Simon Stevens, NHS England Chief Executive.

When the time comes, and you get that text, book an appointment to get your vaccine it is the best protection you and your loved ones will receive from this deadly virus, he said.

Since the UK's vaccination rollout began in December 2020, more than 28 million people have been vaccinated with a first dose in England, 63.8 per cent of the total population of adults aged over 18.

NHS staff have also carried out more than 10 million second doses and has been reminding people to attend their second dose to ensure they receive maximum protection.

NHS Medical Director, Professor Stephen Powis, said: It is testament to the hard work of NHS staff that we are now able to vaccinate people in the next age group.

If you are aged 44, when you are invited to do so, please do book your jab as appointments become available it is simple, effective and provides vital protection against the coronavirus.

The NHS currently vaccinates against COVID-19 using three approved vaccines, Pfizer/BionTech, Moderna, and Oxford/AstraZeneca. People who cannot go online can call the service on 119 instead to book their jab.

Text invitations appear as an alert from NHSvaccine , including a web link to the NHS website to reserve an appointment.

Vaccinations are now being administered at more than 1,600 sites across the country, including churches, mosques, temples, museums and rugby grounds, to ensure the vast majority of people live within 10 miles of at least one vaccination service.