I think people will be watching to see if the requirements the EU are planing to impose -- people who are vaccinated, who have negative test or recovered -- will cause case rates to go up again in October and November from the summer travel they are planning to allow, including Americans.
US will also have a lot of travel activity, though without as stringent requirements. One exception would be Hawaii, which still requires negative tests or otherwise people have to quarantine or go back. Hawaii has been taking in tourists for a few months now but they haven't seen big surges and they have high vaccination rates for their own residents.
So if EU and US don't see surges from October onwards, it will be a good sign for vaccination.
Maybe that would encourage Australians to try to salvage the peak season this November through February, spending on the progress of vaccinations there.
Nope. No chance AU (or NZ) will open up more until all those who want to be vaccinated have the jabs. The AU states are extremely conservative and risk adverse. In AU not all will have had the first jab by 31 Dec 2021 (supply issues) The 2nd jab for all will be several months later. NZ is ~3 months behind AU in vaccination plans. The vaccination stop
you getting very sick and dying.
For me AU & NZ will open up to the world close together. AU followed by NZ. If any chance of community transmission the trans Tasman bubble will slam shut (AU individual states & NZ).
AU & NZ have not had a death due to CV19 (from local transmission) for many months. Currently no-few CV19 restrictions, no lock downs, no masks in most situations, no group restrictions, no travel restrictions [does vary a little by state - area]. Life is 95% as it was in 2019. Federal, South Aust and Victoria state elections due in ~2022. The incumbents will not take any risk.