Senior health chiefs are calling on people to get their booster jabs to prevent tighter Covid restrictions from being implemented at Christmas.
There is mounting concern over rising Covid infection levels ahead of Christmas, with Health Secretary Sajid Javid warning that cases could reach 100,000 a day.
The government has insisted that Covid Plan B - which includes mandatory use of face masks - would only be activated if the NHS came under “significant pressure.”
NHS England’s national medical director Professor Stephen Powis said getting a booster will “protect the freedom and Christmas that we have all earned”.
But who is eligible for a booster vaccine, and how do you book one? This is what you need to know.
When can I get my booster jab?
The NHS Covid-19 booster campaign is now underway, with GP-led local vaccination services now in the process of contacting eligible patients.
Letters and texts were sent out to some 1.5 million people from 20 September inviting them to book an appointment.
People may also be notified by letter or by their GP to arrange a booking.
The JCVI has said people should receive their booster dose at least six months after they received their second coronavirus jab.
How do I book my booster jab?
In England, people should receive a letter or a text inviting them to book their booster vaccine dose when they are eligible.
Once you have been invited to book, you can do so online via the NHS national booking system.
You can only book your booster jab online if you have been contacted by the NHS and you are either:
aged 50 and over
aged 16 and over with a health condition that puts you at high risk from Covid-19
The booking system will only allow you to book your third dose if it has been at least six months since you received your second jab.
You should wait to be contacted by the NHS before booking your booster. You may be asked to book this online or at a local NHS service, such as your GP surgery.
If you have had a positive Covid-19 test, you will need to wait four weeks before booking your booster from the date you had the test.
If you are in Scotland, the NHS inform website features a handy tool which explains how you will be invited for your booster vaccination.
In Wales, you will be contacted by your health board when it is your turn to book your jab. You should not contact your GP to ask about appointments.
In Northern Ireland, the booster programme has already started with residents and staff in care homes being offered a dose. GPs will shortly be starting to invite their older patients in first to receive their booster. You should wait until you are contacted to book an appointment.
Which vaccine will I get?
Those eligible for the booster will be offered either a full dose of the Pfizer vaccine, or a half dose of the Moderna vaccine.
These vaccines will be used regardless of which jab individuals had for their first two doses as these have both been shown to provide a strong booster response.
In cases when neither of these vaccines can be offered, due to an allergy for example, the JCVI advises that the AstraZeneca vaccine can be used for those who received this jab for their first and second dose.