Occasionally, Coronacast gets a question from the audience that not only stumps them, it stumps the expert scientists as well.

And this week, that question came from Helen who was wondering how many people before her had COVID and passed it on to someone else, stretching all the way from her back to Wuhan in China.

It raises many interesting questions about viral evolution and how we can reduce the number of infections globally.

Also on today's show:

* BA2 Omicron sub-variant becoming more and more dominant, according to NSW Health Minister Brad Hazzard

* Coronacast will be dropping back to weekly. We'll be out every Wednesday so watch your feed!