Health secretary Sajid Javid accepted a recommendation from the Joint Committee on Vaccination and Immunisation (JCVI) that the booster programme should be extended to include people aged 18 and over.
The jab was previously available to anyone over the age of 40, healthcare workers and other individuals with underlying health conditions which put them at risk of serious illness if they catch Covid.
The discovery of the new, more transmissible variant Omicron has led the government to bring back mask-wearing rules, tighten up restrictions on international travel and change the guidelines around receiving a Covid booster.
Now those aged 16 and above who are severely immunosuppressed who have received three doses can get a fourth jab too, while people aged between 12 and 15 can get their second shot of the vaccine.
When can I get my booster?
Javid explained that people will be called forward by the NHS at “the appropriate time” – and so those aged between 18 and 39 will not be able to book on the NHS website immediately.
If you’ve already booked your third jab but want to move to a closer date, you might have to cancel your original booking and make a new one.
The booster will be offered in order of descending age groups so that those who are older, or those who are at higher risk of catching the virus, are jabbed first.
The new rules also mean the gap between the second vaccination and the booster jab has been shortened from six months to just three months.
Deputy chief medical officer Professor Jonathan Van-Tam said the NHS would outline in the “new few days” how this process will be “operationalised”.
Why should I get my booster?
After two doses of either vaccine, effectiveness against symptomatic disease appears to wane over time.
The findings of new research show that two weeks after receiving a Pfizer booster dose, protection against symptomatic infection was 93.1% in those who had initially received Oxford/AstraZeneca, and 94.0% for Pfizer/BioNTech.
While experts say vaccine effectiveness against severe outcomes, such as hospital admission, remains high for several months after completing the primary course, researchers have seen greater waning in older adults and those with underlying medical conditions compared with young, healthy adults.
Professor Wei Shen Lim, chair of Covid-19 immunisation for the JCVI, said in a Downing Street briefing in November that boosters “markedly” strengthen protection against coronavirus.
It remains unclear if the vaccines will be as effective against the Omicron variant as they were against the previous Covid strains, but the JCVI has explained that alongside the new mask-wearing rules, the booster programme will help raise levels of public protection.
The health expert explained: “Having a booster dose of the vaccine will help to increase our level of protection against the Omicron variant.
“This is an important way for us to reduce the impact of this variant on our lives, especially in the coming months.
“If you are eligible for a booster, please take up the offer and keep yourself protected as we head into winter.”
Why does anyone need a booster jab?
We already know people require two doses of the Covid vaccine for the best level of protection.
That protection remains strong for a minimum of three months up to six months (for the Pfizer jab in particular), but scientists signalled early in the vaccine rollout that a booster would be needed for the most vulnerable.
Dr Mary Ramsay, head of immunisation at the UKHSA, said: “We know that in older age groups, protection from the first two vaccines is beginning to wear off, leaving millions that need extra protection as we head into winter. That is why it is critical that you come forward for your booster as soon as you become eligible so we can drive down hospitalisations and deaths over the winter.”
As Javid previously said of boosters: “We need to learn to live with this virus. Our first Covid-19 vaccination programme is restoring freedom in this country, and our booster programme will protect this freedom.”
How do I book my Covid booster jab?
Those eligible for the booster jab will be invited to take the vaccine in the priority order set out by the JCVI. Like the flu jab, you’ll be able to get the booster at your pharmacy or your GP.
Boosters are also being given to those who are eligible for a third jab at walk-in vaccination sites across England, with no appointment needed.
You can use the NHS online walk-in finder to check where your nearest centre is. Pharmacies, GP practices and other community sites are being used.
NHS England said almost every person registered with a GP practice lives within 10 miles of a fixed vaccination site – but also stressed that do not need to be registered with a GP to use a walk-in site.
Have booster jabs been tested?
The Cov-Boost study, led by University Hospital Southampton NHS Foundation Trust, was backed by £19.3m of government funding. Thousands of volunteers received a Covid vaccine booster over the summer in a trial that tested seven different vaccines for the impact of a third dose on immune responses.
It was this research that informed the JCVI’s guidance on booster jabs and the autumn booster programme.Data from Israel has since indicated that booster jabs could prevent Covid-19 deaths over Christmas and through the winter.
Deputy chief medical officer for England Professor Jonathan Van-Tam, speaking at the Downing Street briefing, said: “They’re showing that in people aged over 60 in Israel, after a messenger RNA booster, and compared with simply having received the first two doses of Pfizer – in the case of Israel three to four weeks apart – they are observing a tenfold reduction against all Covid infections, an 18.7-fold reduction against hospitalisations, and a 14.7-fold reduction against mortality, and that’s on top of the initial course of Pfizer.
“So I believe therefore that if the booster programme is successful, and with very high uptake, we can massively reduce the worry about hospitalisation and death due to Covid at Christmas, and for the rest of this winter.”
Which vaccines are used for boosters?
The JCVI advises a preference for the Pfizer-BioNTech vaccine for the booster programme, regardless of which vaccine brand someone received for their first and second doses.
This follows data from the Cov-Boost trial that indicates the Pfizer-BioNTech vaccine is well tolerated as a third dose and provides a strong booster response.
Alternatively, the Moderna vaccine may be offered, but as a half-dose booster shot after studies showed it was effective with few side-effects.
Where either of these two mRNA vaccines cannot be offered, for example due to allergies, the AstraZeneca vaccine may be considered for those who received it previously.
This article originally appeared on HuffPost UK and has been updated.