Most people in England, about 30 million, are to be offered the flu vaccine this year, the government says.
It is to prepare for a winter that could see the annual flu season coincide with a surge in coronavirus.
The traditional flu programme will include all over-50s for the first time, as well anyone on the shielding list and the people they live with.
Also for the first time, children in their first year of secondary school will all be offered the vaccine.
Plans for Scotland, Wales and Northern Ireland have not yet been announced.
How bad will flu and coronavirus be?
Flu, which can be deadly or need hospital treatment, poses additional threats during the pandemic:
- There is some evidence a double infection with coronavirus and flu is more deadly than either alone
- A big flu season combined with coronavirus could overwhelm hospitals
- If lots of NHS or care-home staff are sick with flu, then it may not be possible to respond to Covid-19 in the same way as during the peak in spring.
But it is impossible to predict how big a flu season we will have.
Australia, which is currently in its winter, is either having a very mild or very late flu season.
Social-distancing and hygiene measures in place to stop coronavirus should, in theory, also have an impact on the amount of flu going around.
It is also uncertain how bad coronavirus will be, although a rise in cases from the autumn onwards is seen as plausible by health officials.
Who will be offered the flu vaccine?
- people who were required to shield from coronavirus and anyone they live with
- people with some medical conditions including diabetes, heart failure and asthma
- pregnant women
- pre-school children over the age of two
- all primary school children, as last year, and, for the first time, Year 7 pupils
- initially all people over 65, before the programme is extended to the over-50s
The government wants to ensure the highest risk patients are at the front of the queue when the immunisation programme starts in September.
Those aged 50-64 will be offered the jab later, with the full details still to be announced.
Last winter, 25 million people in England were offered the flu vaccine.
Health Secretary Matt Hancock said: “This will be the biggest flu vaccination programme in history and will help protect our NHS as we head into winter.
“If you are eligible for a free vaccine, whether it’s for the first time or because you usually receive one, then I would urge you to get it, not just to protect yourself but to protect the NHS and your loved ones from flu.”
Plans are also being put together for ensuring coronavirus does not disrupt vaccination by, for example, causing schools, which deliver the childhood programme, to shut.
Prof Chris Whitty, the chief medical advisor, said: “This winter more than ever, with Covid-19 still circulating, we need to help reduce all avoidable risks.
“Vaccinating more people will help reduce flu transmission and stop people becoming ill.”
Children are “super-spreaders” of the flu virus.
But the expansion of the childhood programme had not been anticipated before the pandemic.
The plan had been to assess the impact of vaccinating all primary school children, achieved for the first time last year, before deciding what to do next.
Meanwhile, there will be a renewed push to persuade health and care workers to have the vaccine.
Last year, 74% of staff were immunised.
Paulette Hamilton, from the Local Government Association, said: “Extending the free winter flu jab to as many people as possible is essential if we are to tackle two potentially deadly viruses head-on and prevent one seasonable and predictable virus creating the conditions for a second, more serious and unpredictable deadly second wave of Covid-19.
“It is absolutely critical that all our health and care workers get themselves vaccinated, to protect both themselves and the people they look after, including our elderly and most vulnerable, from a potentially devastating second wave of infections.”
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