I've spent time studying abroad in Vietnam so I think I can answer honestly.
One day, I went camping with some friends. We then returned to the capital and 2 days later I saw the high rise she lived in on the news. She lives in a high rise that's about 38 floors, with around 30 units per floor, so that's about 1000 units. Someone who lived somewhere in that high rise had tested positive for covid so they placed the building under a police barricade. A couple days later they limited the restrictions to only the floors the patient (zero) had been to.
Right now they're experiencing a really bad covid outbreak, and I'm not entirely confident that this isn't the big one that will lead to non-stop community transmission like in the US.
There are a ton of foreigners in the country, I know maaaany people working for embassies from western countries, if there are shady stuff going on you would hear it from them.
A recent development is that they aren't publishing the schedules of an infected person anymore. Before they use to say:
J.S who works at the Samsung Plant on 14 Main St. on the 14th of May visited the Starbucks from 2pm-3pm on Xuan Dieu street, then he visited the au co flower market from 3pm-4:30pm, and then went to Karaoke with colleagues at 54 Blueberry Lane from 5pm-9:30pm, afterwhich he took a cab home whose driver has not yet been identified.
And they would do that for every day since their suspected time of infection. So it was extremely privacy invasive but it helps with contact tracing. Now they will just announce the locations, I presume it's because there's too many new cases.
Recently in the news there was a couple who tested positive for covid but wouldn't come out of their house for 2 or 4 hours against police & health worker's demands. If you have covid, you are forced into hospitalization so you can be monitored by doctors and not infect others.
If you so much as went to the same grocery store at the same time as a covid patient you're going to get sent into centralized quarantine.
They know they can't handle millions of cases so they have to crack down hard on any cases. The death toll last week was only 30, it's these part few weeks that it's been steadily going up.