A single payer healthcare system is a system where all citizens have government health insurance. Now most countries with single payer healthcare allow people to buy supplemental private insurance, though some have restrictions on what that supplemental insurance can cover.
In any case, several 2020 Democratic Presidential candidates, including Bernie Sanders and Elizabeth Warren, support a single-payer healthcare system where supplemental private insurance plans are not allowed to offer duplicative coverage, i.e. they’re not allowed to cover any of the same benefits that the government plan covers. They’re only allowed to cover benefits not covered by the government plan.
My question is, which countries with single payer healthcare have a similar ban on duplicative coverage? I think Canada may be one. Are there any others?