Honestly we don't know. Some of their success is obviously keeping the virus away from their elderly population, because a much smaller percentage of their elderly population is getting it, but even broken down by age their mortality is lower than ours and Italy's for each age group. It could be that there is just a large asymptomatic carriage rate we aren't appreciating, but Italy is swabbing heavily as well and isn't seeing it, and when we monitored the cruise ships we didn't see a very large asymptomatic carrier rate there either (it existed but was a minority of cases). Italy also isn't doing anything that differently from Korea, in terms of public health, and for some reason they are seeing their hospitals flooded in a way that isn't explained just by the age and health characteristics of their population. Even China has a lower case fatality rate for each age group than Italy despite having a fraction of the ventilators, and the only difference I can appreciate in China's favor is that China was also an early adopter of hydroxychloroquine.
My main point, though, wasn't to say that we definitely should or shouldn't use these therapies, it was to say that in the absence of definitive studies and recommendations its not wrong to develop a plan of care based on following other physician groups rather than waiting for CDC guidelines to catch up. At this point the situation is so fluid that chances are that if you do your best to make an informed decision chances are whatever you decide upon is endorsed by at least one 'reputable source' somewhere in the world.
