This winter’s flu season could be more challenging than previous years due to a lack of confidence in the vaccine and low natural immunity due to lockdown, Sajid Javid warned.

The Health Secretary said the potential problems from flu underlined the need to lift the remaining coronavirus restrictions in England this summer rather than risk a wave of Covid-19 cases coinciding with the annual NHS winter pressures.

The Government has targeted July 19 to lift the major remaining restrictions and Mr Javid said that while he understood concerns about the approach, it was a matter of getting it done before the winter.

He warned that experts had concerns about the impact of flu this winter because of the lack of natural immunity because of low prevalence during the lockdown last winter and “less confidence” in this year’s vaccine due to a lack of data from southern hemisphere cases.

“There are people who are anxious and want us to be more cautious with opening up and I totally understand that, I absolutely get that,” he told the Local Government Association conference.

“But all I would ask them to think about is that if you don’t start opening up now, when? When would you do it?

“Because opening up now, going into the summer, all the public health officials that we have, the scientists, our epidemiologists are saying that it’s much better to open up going into the summer – for lots of reasons – than just waiting to do it in the winter.”

This winter “we have a much lower level of immunity than we normally have” to flu because of the lack of cases in 2020/21.

And the development of a vaccine is usually helped by examining cases in the southern hemisphere winter but “there wasn’t much flu going on there either”.

“So it means that although there is a vaccine, scientists have a lot less confidence in that vaccine than they normally do,” he said.

“So you put all that together – we’ve got all the flu pressures that you would normally expect and obviously Covid still around – so we do need to start opening up.

“We feel very comfortable with the plans we have set out, despite the rise we are going to see in infections.”

Mr Javid said cases would be “a lot higher” by July 19 and “into August they are going to be even higher than that”, but the vaccines were working.

The Health Secretary indicated that demand for flu jabs could be “dramatically” increased by the plan to offer Covid booster shots at the same time.