Sir Patrick Vallance, England’s chief scientific adviser, has defended the government’s approach to tackling the coronavirus, saying it could have the benefit of creating “herd immunity” across the population.

Critics including the former health secretary Jeremy Hunt have expressed concern about the decision to delay more drastic measures, such as school closures.

However, Vallance said the government’s approach was aimed at broadening the peak of the epidemic, and allowing immunity to build up among the population.

“What we don’t want is everybody to end up getting it in a short period of time so we swamp and overwhelm NHS services – that’s the flattening of the peak,” he told BBC Radio 4’s Today programme.

Q&A How can I protect myself and others from the coronavirus outbreak? Show Hide The World Health Organization is recommending that people take simple precautions to reduce exposure to and transmission of the coronavirus, for which there is no specific cure or vaccine. The UN agency advises people to: Frequently wash their hands with an alcohol-based hand rub or warm water and soap

Cover their mouth and nose with a flexed elbow or tissue when sneezing or coughing

Avoid close contact with anyone who has a fever or cough

Seek early medical help if they have a fever, cough and difficulty breathing, and share their travel history with healthcare providers

Advice about face masks varies. Wearing them while out and about may offer some protection against both spreading and catching the virus via coughs and sneezes, but it is not a cast-iron guarantee of protection Many countries are now enforcing or recommending curfews or lockdowns. Check with your local authorities for up-to-date information about the situation in your area. In the UK, NHS advice is that anyone with symptoms should stay at home for at least 7 days. If you live with other people, they should stay at home for at least 14 days, to avoid spreading the infection outside the home.

“Our aim is to try and reduce the peak, broaden the peak, not suppress it completely; also, because the vast majority of people get a mild illness, to build up some kind of herd immunity so more people are immune to this disease and we reduce the transmission, at the same time we protect those who are most vulnerable to it. Those are the key things we need to do.”

He added: “This is quite likely, I think, to become an annual virus, an annual seasonal infection.”

Downing Street’s approach, announced by Boris Johnson at a press conference on Thursday, contrasts with that of countries including Ireland and France, where schools are being shut down.

With experts from the “nudge unit” involved in determining how to shape the government’s response, the shadow health secretary, Jon Ashworth, asked the health secretary, Matt Hancock, earlier this week for reassurance that the approach was not based too much on behavioural science.

But Vallance sought to underline that it is the epidemiology that is guiding the decision not to impose more draconian restrictions on the public’s day-to-day lives immediately.

“If you suppress something very, very hard, when you release those measures it bounces back and it bounces back at the wrong time,” he said. The government is concerned that if not enough people catch the virus now, it will re-emerge in the winter, when the NHS is already overstretched.

Hunt, who is now chair of the health select committee, has said he is concerned that the government is allowing schools to remain open and large gatherings to go on as normal.

He criticised the government for not going far enough and said the UK’s response made it an “outlier” when compared with other countries that have taken more robust measures.

Johnson announced on Thursday that anyone with coronavirus symptoms, however mild, such as a continuous cough or high temperature, must stay at home for seven days. He also said school trips abroad should be stopped, and people over 70 with serious medical conditions should not go on cruises.

But Hunt suggested the government failure to take more stringent actions could lead to more people catching the virus and that schools should only remain open for the children of key workers.

“Its extremely grave,” he said. “We are in a national emergency … Many people will be very concerned [by the decision to keep schools open and not cancel large events].

“The other message from the press conference was that if we are to give people the care they need, when the worst hits us, we need to ‘flatten the peak’ and spread the pressure on the NHS … I’m personally surprised that we’re still allowing external visits to care homes.”

He said the issue was not necessarily whether healthy people became infected at football matches – all of which were suspended on Friday morning until 3 April, though rugby games are still scheduled to take place – but who they went on to meet in the days afterwards.

“Whether we then go on to have tea with our friend who’s recovering from cancer, our grandfather, grandmother,” he said. “That’s the issue. I think it is surprising and concerning that we’re not doing any of it at all when we have just four weeks before we get to the stage that Italy is at.

“You would have thought every single thing we do in that four weeks would be designed to slow the spread of people catching the virus.”

He agreed that the government’s decision to keep schools open and allow large sporting events to continue cast the UK as an “outlier” in western Europe for its response to the coronavirus outbreak.

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Today in Focus Can the NHS cope with coronavirus? Sorry your browser does not support audio - but you can download here and listen https://audio.guim.co.uk/2020/03/12-76989-20200312_TIF_NHS.mp3 00:00:00 00:27:05

The death toll in Italy has passed 1,000 people and Ireland, which shares a land border with the UK, announced on Thursday it would close schools, colleges and other public facilities for a fortnight.

Jimmy Whitworth, a professor of international public health at the London School of Hygiene and Tropical Medicine, also said he was surprised stronger measures had not been introduced, but expected they would come in the next fortnight.

“Based on evidence from other countries the most realistic approach to this is to initiate the strongest public health measures that will be supported by the general British public,” he said.

“I am surprised that stronger measures haven’t been introduced at this stage but I anticipate that they will come in the next week or two.”