People aged 16 and over who are severely immunosuppressed can book their booster online from today (Monday 31 January).
The online booking system has been updated to allow booster bookings for severely immunosuppressed people.
There are around 400,000 people who are severely immunosuppressed who are eligible for a fourth jab - at least three months on from their third dose - and are able to book a month in advance of that.
This group includes people having treatment for conditions such as cancer or those with long-term chronic conditions where their condition puts them at greater risk if they were to get COVID.
Previously, the NHS contacted people who are eligible for additional doses of the vaccine and GPs and their clinicians were also asked to identify and invite them for their vaccinations.
People who are severely immunosuppressed are also able to access walk-ins across the country, following instructions on the walk-in finder or book a fourth dose appointment online to get protected.
The change to the online service will make it even easier for people to plan and book their top up vaccinations.
So far, more than nine out of ten of those who are severely immunosuppressed have had a third COVID-19 vaccination.
Professor Stephen Powis, NHS National Medical Director, said:
It is incredibly important that those who are most at risk from coronavirus continue to come forward for their doses whether it's a fourth dose or booster vaccine when their treatment allows and it is fantastic to see that more than nine in 10 people who are severely immunosuppressed have had their third dose so far.
As more people who at the highest risk from COVID become eligible for their booster jab they will benefit from being able to book an appointment online at a convenient vaccination centre.
Getting the vaccine is the best way to prevent the likelihood of becoming seriously unwell from covid and is all the more important if you have a weakened immune system in helping ensure you are protected.
Health and Social Care Secretary Sajid Javid said:
Our vaccines are the best line of defence against this virus and it is vital those who are most at risk get their third and fourth doses when eligible, to ensure they have as much protection as possible.
The NHS is making it even easier for them to book an appointment, with online bookings now open.
Decisions on when to get a fourth jab for people who are severely immunosuppressed is made between patients and their clinicians, and the majority of fourth doses are being administered through hospital consultants and GPs.
The NHS has delivered more than 115 million doses of the COVID vaccine across England, including 43 million vital boosters, more than 40 million first doses and 31 million receiving a second jab.