is there benefit in doing this over two AZ and one of moderna etc?
My own reasons derive from my daily proximity to some very sick people. Technically, 3jab better than 2jab, and mix and match better than same same, and my PZ interval was 3 weeks.
Now having said that, the data is nowhere at a level where ATAGI/TGA can recommend one way or another yet.
For the general population, its a little bit like the "more is better" crowd. If 2 is good then 5 must be better. In the same vein, if 2 is good then 3 must be better. But is it?. Better in what way? - that the measured antibody levels are higher?. But does that translate to lower infection rate?. Assuming yes is basically the pseudoscience of the "more is better" crowd.
Some people may benefit, some maybe not. Perhaps a targeted approach is all that we need. So it will becomes a question of to what degree is "more is better".
What I am not clear on is whether AZ after 2PZ has any problems. AZ after 1PZ seems OK.
What is clear is that as the population heads to in excess of 90% 16yrs+ 2jab, that the risk of severe covid is drastically reduced. That means that for most people there is now time to wait for official evidence. For others like me, the wait and see approach may not be as comfortable
I am also acutely aware that large parts of the world's population remain unvaccinated while we in AU can comfortably/casually talk about 3jabs. And that is an important equity issue.
International travel by a fully vaccinated person into a less vaccinated country can potentially cause havoc in that country. The fully vaccinated can carry and transmit Covid - albeit at lower levels and for shorter periods of time. So while we advocate for the opening up of borders, lets make sure we don't inadvertently become like the Spanish who decimated the Aztecs with smallpox.