The NHS is to embark on the most ambitious programme of flu jabs in its history amid warnings of up to 60,000 deaths.

The health service aims to immunise a record 35 million people – more than half the UK’s population – against influenza as the country faces its first winter with Covid and flu circulating at the same time.

Experts fear the coming flu season could be particularly deadly because the population will have lost much of its immunity to the virus, which dropped to extremely low levels under Covid restrictions.

With people mixing far more freely than last winter, scientists fear a wave of influenza will coincide with seasonal rises in Covid and other infections such as respiratory syncytial virus (RSV), creating a “triple whammy” for the NHS.

Modelling from the Academy of Medical Sciences has warned of 15,000 to 60,000 deaths from influenza this winter, making the season more than twice as deadly as an average year.

Health officials said that for the first time, newly trained vaccinators will be allowed to administer the flu shot so that more people than ever before can receive the jab before any winter surge. The training will follow guidance drawn up by the UK Health Security Agency, formerly Public Health England.

A campaign launched on Friday by the Department of Health, the Royal College of GPs, the Royal College of Midwives and other professional bodies urges those eligible to book their free flu jab as soon as possible and take up the Covid booster when invited.

Free flu shots are available for about 30 million frontline health and social care workers, pregnant women, people aged 50 and over, those at clinical risk, and children up to school year 11. In many cases the same people will qualify for Covid boosters, which are given no sooner than six months after the second dose of Covid vaccine. Where possible, vaccination sites will offer both shots at the same appointment.

To date, 1.7 million people in England have received Covid boosters. The Joint Committee on Vaccination and Immunisation has recommended boosters for all over-50s, clinically vulnerable people and frontline health and social care workers. The rollout of Covid vaccines in the UK has saved an estimated 130,000 lives and prevented up to 24.3m infections, according to the UK Health Security Agency.

“Not many people got flu last year because of Covid-19 restrictions, so there isn’t as much natural immunity in our communities as usual. We will see flu circulate this winter; it might be higher than usual and that makes it a significant public health concern,” said Prof Jonathan Van-Tam, England’s deputy chief medical officer.

“Covid-19 will still be circulating and with more people mixing indoors, sadly some increases are possible. For the first time we will have Covid-19 and flu co-circulating. We need to take this seriously and defend ourselves and the NHS by getting the annual flu jab and the Covid-19 booster when called.”

The call for people to take up the vaccinations came as an Opinium survey commissioned by the Cabinet Office revealed that more than a quarter of people (26%) did not know that influenza could be fatal, while nearly a third (32%) were unaware that flu and Covid could circulate at the same time. An average flu season kills about 11,000 people in England.

More than a third (37%) of pregnant women – a group eligible for free flu shots – did not realise they could catch influenza if they had been vaccinated for Covid. Flu jabs can be booked at GP practices or local pharmacies, and pregnant women can request a jab at the local maternity service.

“We are facing a challenging winter but we can all help ourselves and those around us by taking up the Covid-19 booster and flu vaccine if eligible,” said Dr Jenny Harries, the chief executive of the UK Health Security Agency. “Getting vaccinated against both viruses will not only help to protect us and our loved ones but will also help protect the NHS from potential strain this winter.”