Using a country that had not given out boosters, like the USA or UK until recently, you’d get a better idea of the efficacy of the vaccine against Delta infections.
Moreover even in Israel the daily cases among double vaccinated are less than those among the unvaccinated. Look at the chart here https://www.ft.com/content/a1b2fd70-71b5-4e91-be0b-553b0e1e2... The line for “Two dose” cases per 100k among over 60 year olds is below unvaccinated since august 15 and continually remains less.
90%? No, that’s too high, but for instance data from public health England is saying the vaccines have around 15-45% efficacy (or 40-80% if doses 8+ weeks apart) against covid-19 infection after 25+ weeks, not 0%. https://mobile.twitter.com/EricTopol/status/1437890711139995...