Here is a great article from Reuters about two nations, South Korea and Italy, with single payer systems, and how each has responded to the virus crisis. South Korea has laws that override often silly, bureaucratic privacy laws (I have said from the start of HPPA that we overdid the interpretation of those regulations) and Italy was too quick to localize testing. But either way, the two nations are able to better track people for helping them than the US can.
I saw at Breitbart.com, the poisonous right wing website, how they were "fact checking" this and had to first, sheepishly admit both nations have single pay (Italy's single pay system is considered very efficient, unlike the usual Italian government cultural comments people often make), and making it sound like AOC's tweet on the topic of single payer and South Korea is bullshit. Her tweet did ignore Italy, to be sure. But to think that simply because South Korea is also relying on a private company to help puts AOC's tweet to a lie is way off. AOC and Bernie have been clear about their support for a mixed economy, and it is just fine for them and me to have public-private partnerships working for the good of our communities and our nation.
Chalk up Breitbart's "fact-check" as another example of "Denmark isn't socialist, but if you call for anything Denmark has, you're a socialist-commie!"