If the numbers of severe cases really are between 15-20% like people have said, then it will overwhelm the capacity of even the best health care systems, because no country is going to have enough hospital beds, much less ICU beds for that. And that's not even taking into account lost wages, stock crash, and economic recession that will result. And that's not even getting into deaths, either from coronavirus or anything else deadly that someone else gets during a period when the hospitals are overflowing. This could be much, much worse than people expect.