It's actually a really interesting question.
It's become apparent Australia's politicians won't accept any cases of community transmission. If Australia's vaccine of choice (Oxford/ Astra Zeneca) is 70-90% effective, seemingly dependent upon the final dosage regime, some might get sick, some might die if they come in to contact with a COVID case.
The politicians are still going to have to make some decisions around the risk they're willing to accept and how that's going to translate when it comes to opening up the international borders.