According to information on the UK’s National Health Service (NHS) website, your EHIC will remain valid for the duration of your trip if your visits starts before exit day.
However, if you are travelling to Switzerland after Brexit, your EHIC may not be valid.
As general advice, the NHS advises all people travelling to the EU or Switzerland to take out health insurance whether their trip is before or after Brexit.
You should also speak to your doctor and insurer if you have a pre-existing health condition.
For the latest information on Brits’ access to healthcare in Switzerland, see the NHS website here.
The UK and Switzerland have signed a citizens’ rights agreement which guarantees that Brits living in Switzerland before Brexit will continue to enjoy the same healthcare entitlements they currently do.