Britain may need Covid booster jabs to prevent a “winter surge” of cases, one of Britain’s top vaccine advisors has said.

Professor Adam Finn, a member of the Joint Committee on Vaccination and Immunisation (JCVI), said Britons may well need boosters in the latter part of this year, should medical evidence show that the effects of the initial immunisations are wearing off.

He told Sky News that if booster doses are needed, they should go “in the first instance for the people who had the vaccine (the) longest time ago and who are at highest risk of getting seriously ill when they get infected”. This would mean the elderly and healthcare workers who were first to be jabbed.

Professor Finn added: “I don’t think this is a certainty yet, but I think there’s a high probability that at least some boosting will need to go on this winter.” However, he emphasised, it is far too early to know what requirement there will be, adding: “We will learn as we go along.”

The professor acknowledged that a key issue in the event of a booster campaign will be the scale of the pharmaceutical distribution challenge, as it has taken more than half a year to get through the majority of the population and it is “not really feasible” to expect a much faster roll-out, despite the increased supply on offer as more vaccines are approved and available.

Professor Finn’s comments come at a time when all remaining adults are now able to book a vaccination and 83 per cent of the adult population has now had at least one dose. With 61 per cent having had two and all over-50s expected to have had both jabs soon, the most vulnerable groups have nearly been covered.

Attention is now shifting to other matters. NHS Chief Sir Simon Stevens has said plans will soon be published for a major autumn flu vaccination campaign, while efforts are being made to encourage eligible people from groups with a low take-up of vaccinations to come forward, especially ethnic minorities.

The issue of whether to vaccinate children as young as 12 is also under consideration. Earlier this month the Pfizer vaccine was approved for use in this age group in the UK, as it has been in many other countries.

While the government has not yet decided on this, a Pfizer official in Israel, where the company’s jab has been widely rolled out and studied, has stated it is still very effective against the Delta variant first seen in India.

This variant is now responsible for the majority of UK cases, with a recent rise leading to the planned ending of Covid restrictions on June 21st being cancelled. Most of the cases and hospitalisations have been among younger age groups and those who have not been vaccinated despite being eligible.

Britain’s third wave may prove much weaker because of the benefits of vaccination, which is not only reducing hospitalisations and deaths, but appears to have reduced the capacity of outbreaks to grow in local areas.

This has been seen in locations such as Bolton, Blackburn and Bedford, where a big surge in cases in May has been followed be declining case numbers in the last few weeks.