Posted: Apr 14, 2016 2:37 am
Yes well any reticence previously has been wanting to be very very very sure, as the cost of getting this wrong is enormous, but the connection was pretty clear a while ago and a review of early outbreaks showed the same effect, why it wasn't previously detected really a matter of scale, a very large outbreak will show even relatively rare effects more strongly.
This announcement hinted at earlier in the week when 'scarier than thought' was mentioned.