FDR, not all countries will peak at the same time. That is why International travel needs to remain locked down. In addition we have the possibility of “medical refugees” rich Asians are quite capable of swamping Australia’s health system if they decide that it is not desirable to remain, for example, in India. Then we have the hubs like Dubai, Singapore, Heathrow, Frankfurt, etc, where transit passengers can get infected.
As for international tourism, I made the point as did poster “poteroo” that us retired boomers spend considerable money on overseas travel in our declining years, however this years plans are cancelled and it is way too early to consider tourism in 2021, that is if we can still afford it and presuming we survive.