But I remember very clearly the period in late February and early March when authorities in every country were making that same claim. "We only have a few dozen patients, which is nothing like the true outbreaks in Iran and Italy, we'll surely be able to get it under control without extreme measures." Is there a reason to expect Vietnam's current outbreak will follow a different trajectory?
And some of these countries made good on the claim. New Zealand has 23 active cases. Taiwan has 27. South Korea has 808 (that's after having a cult church being a hotbed of infection and its members actively hindering government intervention).
Hell, even Italy now has only 12,474 active cases.
We're not even a year into a multiple year pandemic. Yes, it's great those countries have it under control now, but I don't feel comfortable assuming it will stay that way.
The US has ~60k daily new cases - that is, 642 new patients about every 15 minutes.