Why so long between scary variants?

It was in early May when the Delta variant was officially listed as a variant of concern.

Delta turned out to be far more contagious than previous variants, and challenged Australia's public health response.

But since then, there haven't been any new variants of concern listed by the World Health Organisation, though there have been a couple of new variants of interest.

So why not? And what do we know about the AY4.2 variant that's causing some concern in the UK?

Also on today's show:

* Should I go overseas on holiday?

* My friends believe that the only benefit of being vaccinated to prevent oneself from severe disease. Is this true?