A very interesting observation [1] was made by Dr John Campbell who noticed a difference between vaccine efficacy in Israel vs UK. In Israel, the doses were spaced 2-3 weeks apart, and the protection against transmissibility has dropped off significantly more than in the UK, where doses were spaced further apart, sometimes over 10 weeks between the first and second dose. His hypothesis was that a longer duration betw…
> You’ve probably seen reports from Israel on low vaccine effectiveness in this wave. Is it because of Delta? Waning immunity? We think the reason is mostly that we got the denominator wrong.
https://twitter.com/dvir_a/status/1420059124700700677
> This is what we got wrong. This “wave” started from cities with high vaccination rate and couldn’t “find” unvaccined adults at risk. The denominator we need to use until mid-July is >95% vaccination rate and not the country’s average.