The numbers from Israel (https://www.bloomberg.com/news/articles/2021-07-05/israel-sees-decline-in-pfizer-vaccine-efficacy-rate-ynet-says) indicate the Pfizer vaccine is quickly losing efficacy against the Delta strain with only 64% chance to prevent symptomatic infection - but critically, none of these articles covering that report indicate if that's for full 2-dose vaccination.
Another recent study "showed the Pfizer vaccine was 84% effective against the [Delta] variant after two doses, but only 34% effective after the first dose." (https://www.nbcboston.com/news/local/pfizer-moderna-jj-vaccines-efficacy-as-delta-variant-concerns-rise/2419162/). The effectiveness rating appears to be the chance to prevent symptoms.
A slightly earlier article (https://www.businessinsider.com/delta-coronavirus-variant-strongest-threat-vaccinated-people-2021-6) places Pfizer efficacy at >= 88% chance to prevent symptoms with full vaccination, but only 33% for partial vaccination.
Intuitively, the numbers from Israel seem to be an outlier. The critical question: Does that statistic mix full vaccination and partial vaccination?
If the numbers are mixed, that would explain why the efficacy was found to be roughly halfway between partial and full (since some people already had 2 doses while others have only 1). If the numbers are for full vaccination... then it's time to talk about booster shots.