That's a fallacy. At any point in time, there will be patients showing up with viral pneumonia in the hospitals, with some seasonal variance.
For there to be a discernible difference here, you need a "critical mass" of cases. How many such cases are necessary depends on the incidence of severe cases vs non-severe cases, but we do not know the amount of non-severe cases, because we did not test everyone.
Antibody studies suggest that there are 10x as many cases as reported. If that is true, then there could have been hundreds of thousands of cases that went undetected along with some more severe cases that were labeled as "viral pneumonia".
The different rates of infection in different countries may well have more to do with the amount of testing than the actual infection rate.