The COVID booster jabs rollout has been extended to all adults aged over 40 from today, it has been announced.

It comes after a recommendation by the Joint Committee on Vaccination and Immunisation (JCVI) and results from the first real-world study by the UK Health Security Agency.

The study shows that two weeks after receiving a booster dose, protection against symptomatic infection for adults aged 50 and over was 93.1% in those who had an AstraZeneca dose, and 94% for Pfizer.

The JCVI, the independent expert advisory committee that advises ministers on immunisation, has also announced that it will be advising that all 16 and 17 year olds have a second dose of the Pfizer vaccine.

Previously, only those in this age group considered to be in an “at-risk” group were eligible.

Second doses for 16 and 17 year olds should be given at least 12 weeks after initial jabs, the JCVI suggests.

The decision to advise the second dose is based on a review of the latest evidence of the benefits of the vaccine programme, compared to the risks of any side effects, they add.

The booster announcement comes as ministers have urged people to get third jabs when called in a bid to save Christmas.

Conservative party co-chairman Oliver Dowden told Sky News it was up to the public whether new controls would need to be imposed this winter.

The JCVI said people should be offered the Pfizer or Moderna jab as a booster, irrespective of which vaccine they had initially.

The body had previously advised booster vaccinations for all adults aged 50 years and over and those at greater risk from COVID-19.

They add that, following two doses of the vaccine, as yet, there is no “robust evidence of a decline in protection against severe COVID-19 (hospitalisations and deaths) in those aged under 40 years”.

So far, some 12.6 million people have had a third COVID-19 jab.

The JCVI says that they will continue to closely review all available data to develop further advice in due course.

Professor Wei Shen Lim, chair of COVID-19 immunisation at the JCVI, said: “Booster vaccine doses in more vulnerable adults, and second vaccine doses in 16 – 17 year olds are important ways to increase our protection against COVID-19 infection and severe disease. These vaccinations will also help extend our protection into 2022.

“If you are eligible, please make sure to have these vaccines and keep yourselves protected as we head into winter.”