Things to consider:
- Population density
- Age demographics
- Health demographics
- Quality of healthcare
- Availability of healthcare
- Concentration of cases
- Quarantine measures
- Availability of tests
- Cultural norms (e.g., shaking hands, kissing, etc.)
- Cultural hygiene practices
- Climate
- Delay between first detection and policy measures
And a whole bunch more that neither of us have probably ever thought of. You can’t just say “the US has a population about 5 times the size of Italy, so multiply their deaths by 5!” And expect people to take you seriously.