[russellw]

Italy, Spain and Colombia make an interesting comparison. They are all similarly sized at around 370M adults but that's where the similarity ends.

Spain and Italy both have more than 600 cases per 100k of population where Colombia has under 250.

Spain and Italy both have more than 70 deaths per 100k of population where Colombia has just 8.

Yes, there is a big discrepancy in testing; the former two countries having tested more than 13% of their adult populations and Colombia less than 2%.

While the lack of testing may well explain the differences in raw case numbers it doesn't explain the low mortality rate because it's not a case mortality rate but a population based one - although the CMR is much lower for Colombia at 3.4% compared to the >13% of the other two countries and more testing would only lower that further.

Climate perhaps?