More than 620,000 people snapped up COVID booster jab appointments over the last two days after the NHS Vaccination programme opened to allow those age 40 and over to book their life-saving top-up three months on from their second dose.

Seven million more people have become eligible to book a jab as a result of the change, which follows new advice from the Joint Committee on Vaccination and Immunisation (JCVI).

They can book two months after their second dose, a month in advance of becoming eligible to receive their top up.

With the NHS COVID Vaccination programme now in its most complex phase yet, the country’s top doctor has called on everyone to play their part in the new ‘national mission.’

The call comes alongside new data from UK Health Security Agency today suggesting that vaccine protection against mild symptomatic disease from Omicron is substantially reduced for two doses, but that boosters showed good effectiveness against the new variant.

NHS National Medical Director Professor Stephen Powis said: “Rising cases of the Omicron variant coupled with the new data today should be a wake-up call for those who haven’t yet had their booster or, indeed, any vaccine.

“NHS staff are expanding the booster programme and so when it is your turn, please book in.

“I want to say a huge thank you to all those who have already come forward since the new rules came in to effect – protecting themselves, their family and their friends.

“And for those who haven’t yet got their jab do not hesitate, book one this weekend”.

Vaccines Minister Maggie Throup said: “I would like to thank the NHS, military and the army of selfless volunteers for their tireless work. I would also like to thank every single one of those 22 million people for coming forward and doing the right thing.

“Getting your booster vaccine is the most important thing you can do ahead of Christmas to protect yourself and your family.”

The NHS launched its official recruitment drive to get more vaccinators and volunteers to help ramp up the booster programme on Wednesday and thousands have already come forward.

These new recruits of vaccinators and volunteers will join the mission to get more jabs in arms from now and over the coming weeks leading up to Christmas.

If you are interested in applying or if you want to volunteer, search ‘NHS vaccine team’ to find out how you can help.

The NHS is also working with the Royal Voluntary Service and St John Ambulance to drum up the support of more than 42,000 volunteers.

The NHS is vaccinating in line with JCVI guidance and is offering boosters to the most vulnerable first before expanding down the age ranges in five-year intervals, through those aged 18 to 39.

Currently those aged 40 and over, health and care workers, and those who are clinically vulnerable can book their appointments through the National Booking Service with a three month gap between their second and booster doses.

In the meantime, existing booking arrangements will remain in place – there is no need to cancel your appointment if people have already booked in.

In just over a year since the NHS launched its COVID vaccination programme, the biggest and most successful in health service history – NHS staff have delivered 100 million lifesaving vaccines, including over 42.9 million first doses, 39.1 million second doses and more than 18 million top ups.

Every eligible adult should have an opportunity to book in for their booster jab by the end of January, and in line with the updated JCVI guidance the health service is inviting people most at risk from the virus first, and is working through age groups in stages before opening up to other age groups.

People can get their vaccine by booking online through the National Booking Service or by calling 119, and GP practices are also inviting those who are eligible.