The extent of the outbreak in Brisbane has become clearer, after authorities revealed that they were dealing with two separate coronavirus clusters.

And at the heart of both outbreaks are health care workers who have somehow contracted it from COVID positive patients in hospital.

As they work closely with patients, healthcare workers are particularly vulnerable to contracting the virus.

But on today's Coronacast, with vaccines now available and a year's worth of knowledge about the virus why are health workers still getting COVID at work?

Also on today's show:

* Is there a case for vaccinating younger populations first considering they tend to be more active within the community?

* Should I cancel my travel for the holidays?

* You mentioned that the AstraZeneca vaccine 'escapes the South African variant to some extent'. Can you talk about that some more?