The second wave in Victoria in 2020 revealed aged care to be a major vulnerability in Australia's handling of the coronavirus pandemic.

Of the many hundreds of deaths from the second wave, the majority were in private aged care homes.

And, sadly, COVID-19 has once again made it back into aged care - with coronavirus currently in two facilities in Melbourne.

So on today's Coronacast, wasn't aged care supposed to be protected by now?

Also on today's show:

* When does a cluster become a wave?

* What research has been done on shortening the gap between 1st and 2nd doses?

* Why can't we just vaccinate people on day 1 of hotel quarantine?