Reports from Israel of lower effectiveness of Pfizer/BioNTech against the Delta variant, ranging from 64-70% against infection/symptomatic disease, are concerning and could have implications with regards to the vaccine coverage and requirement of other non-pharmaceutical interventions to effectively control the spread of SARS-CoV-2.
The effectiveness reported in Israel is lower than the ~80-90% figures seen in the UK however more information on the Israeli data is needed to assess whether this is solely attributable to a difference in terms of testing regimes and/or other confounders. If such differences are ruled out, given Israelis were vaccinated earlier, these lower figures could be due to waning immunity which would have implications for the requirement of booster doses.
Effectiveness of Pfizer/BioNTech vaccine in Israel over time:
Comparison of Israel data against two UK studies, showing effectiveness of Pfizer/BioNTech vaccine over the Alpha and Delta variant:
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