UK vaccine experts say it should be available to everyone over 75, care-home residents and anyone extremely vulnerable aged five and over.

Vaccinations in England and Wales are to start in early April, with Northern Ireland's rollout from mid-April.

Scotland's booster campaign will start in the final week of March.

The Joint Committee on Vaccination and Immunisation (JCVI) said hospital admission rates for Covid-19 in autumn 2022 showed that the risk of becoming seriously ill from coronavirus was noticeably higher in people over 75.

As a result, they would gain the most from protection from an additional vaccine dose this spring, with health chiefs warning against complacency.

Anyone who lives in a care home for older adults and people aged five and over who are defined as immunosuppressed are also to be offered a booster jab.

They include people who've had organ transplants or who have blood cancer, and those undergoing chemotherapy treatment for cancer.

It's advised that the booster vaccine be given six months after someone's previous dose.

Bridging the gap

Professor Wei Shen Lim, JCVI chairman, said: "Vaccination remains the best way to protect yourself against Covid-19, and the spring booster programme provides an opportunity for those who are at highest risk of severe illness to keep their immunity topped up.

"This year's spring programme will bridge the gap to the planned booster programme in the autumn, enabling those who are most vulnerable to be well protected throughout the summer."

The NHS in England is expecting to offer the first spring booster doses to those eligible in April, and the campaign will last until late June. Wales has confirmed it will start on 1 April.

Four different vaccines, made by Pfizer-BioNTech, Moderna, Sanofi/GSK and Novavax could be used.

It's likely most doses will protect against the Omicron variant as well as previous ones.

Since last summer, different versions of the Omicron variant of Covid have been spreading the most - the latest being Omicron BQ.1.

Children under 12 years of age will be offered a children's formulation of the Pfizer BioNTech vaccine.

Dr Mary Ramsay, head of immunisation at the UK Health Security Agency, said Covid-19 was still circulating widely and there had been recent increases in older people being admitted to hospital.

"It is important those at highest risk of severe illness do not become complacent and I would encourage everyone who is eligible to come forward once the booster programme starts."

People at higher risk of severe Covid-19 are also expected to be offered a booster vaccine dose in autumn 2023 in preparation for the winter.

Last autumn, frontline health and care workers, adults aged 50 and over, and some carers and household contacts were offered a booster dose, too.