Fourth-dose Covid booster vaccines increase protection against Covid-19, particularly in people aged over 70, according to a UK trial.

But scientists say any short-term protection against infection is likely to fall away quickly.

The UK rolled out fourth doses to over-75s and the most vulnerable in April.

A larger group of people may be offered a booster in the autumn, but any decision will be based on advice from the UK’s vaccine committee.

It is likely to look at whether new worrying variants are spreading, and Covid pressure on hospitals.

Some countries, such as Israel and Germany, have already started offering all adults a fourth dose.

Who is eligible for a fourth dose?

adults aged 75 and over

residents in care homes for older adults

those aged 12 and over with weakened immune systems

You can book an appointment online three months (91 days) after your previous dose. However, to get maximum protection, the NHS recommends having the spring dose about six months later.