[dynamite]

mRNA ones have faster build up of antibodies, but along with it more adverse effects.
P effectiveness is better only in first 5-6 months, after that is below to S and likes of AZ etc
M continue to perform better but due to higher dose

China is also developing mRNA but doubt it have much takers. 

Anyway inhale methods are the ones to watch next year, 
it is known to be more effective and lower adverse effects.

I think it is quite weird why can the immunity from a vaccine wane off so quickly?