It often takes a crisis to expose all the weak points in a system, and this week's coronavirus outbreak in Melbourne has done just that.

The whole thing started with yet another breach of hotel quarantine. Then there's the slowness of the vaccine rollout, which has left millions of eligible people exposed.

Add to that the state issues of lacklustre QR code usage, and a testing system that is groaning under huge demand.

With herculean efforts by contact tracers and a bit of luck, Victoria mightn't suffer too much damage. Or maybe the virus will get away. It's still too early to know.

But on today's Coronacast, did it have to be like this?

Also on today's show:

* We had our 1st AstraZeneca shot a month ago. We have decided to have the 2nd dose in 8 weeks, rather than 12. What do you think? Also, is clotting risk present with the 2nd shot?

* If I have AstraZeneca for doses 1 and 2, with both shots completed by August, could I have a Pfizer shot in December? Would this provide better protection or could it be harmful?

* I received the first dose of the AstraZeneca vaccine 10 days ago. Can you tell me if I'm less likely to catch COVID-19?