Two weeks ago, a convoy of six buses made its way towards a sanatorium in the small Ukrainian town of Novi Sanzhary. On board were 45 Ukrainians and 27 foreign nationals from South America, recently evacuated from Wuhan in China, on their way to two weeks of quarantine. None had been confirmed to have the coronavirus.

As the convoy reached the bridge that would take it towards the sanatorium, it was forced to a stop: the road had been blocked days earlier and was now guarded by a group of people described by the BBC, Reuters and AFP as “protesters” and “demonstrators”. Burning tyres littered the road...