Israel went very heavily with Pfizer which ended up rather ineffective against Delta. With a more balanced mix they would have probably fared better.
I mean, this isn't true... less effective, sure. But it's not ineffective by any measure.
If they had advertised 42% effectiveness rating when it was first launched they'd have probably gone back to the drawing board. (This is what Pfizer did recently with a second version that was aimed specifically at Delta but didn't fare any better than the first version.)
Read https://www.kff.org/policy-watch/covid-19-vaccine-breakthrou...