Britons should stop "soldiering on" by going to work when sick and making others ill, the health secretary says.
Matt Hancock said people in the UK were "peculiarly unusual and outliers" for still going to work when unwell.
He made the comments in a joint session of the Health and Social Care and the Science and Technology committees.
He also told MPs he would like to see the diagnostic capacity built for Covid used to test for other illnesses like flu once the pandemic had passed.
The UK now has the capacity to carry out over 500,000 tests a day, with new labs to be opened next year to double that number.
He said he wanted to see the "global-scale diagnostics capability" continued to be used.
"Afterwards we must use it, not just for coronavirus, but everything," he told MPs.
"I want to have a change in the British way of doing things where 'if in doubt, get a test' doesn't just refer to coronavirus but refers to any illness that you might have.
"Why in Britain do we think it's acceptable to soldier on and go into work if you have flu symptoms or a runny nose, thus making your colleagues ill?
"I think that's something that is going to have to change.
"If you have, in future, flu-like symptoms, you should get a test for it and find out what's wrong with you, and if you need to stay at home to protect others, then you should stay at home.
"We are peculiarly unusual and outliers in soldiering on and still going to work, and it kind of being the culture that 'as long as you can get out of bed you still should get into work'. That should change.
"This year there's been far fewer respiratory and other communicable diseases turning up in the NHS.
"I want this massive diagnostics capacity to be core to how we treat people in the NHS so that we help people to stay healthy in the first place, rather than just looking after them when they're ill."