Israel's coronavirus Tzar, Prof. Nahman Ash, told the Israeli Cabinet today that the first dose of the Pfizer vaccine appears to be less effective than what Pfizer's study suggested. That's bad news for the UK's "first dose" vaccination strategy.

One reason for this difference could be the older population of vaccine recipients in real practice compared to the study.

Prof. Ash was talking specifically about the *first* vaccine shot, not the full two-shot regimen. Israel is giving the second shot 21-28 days after the first and only began administering second shots last week.

Of course, "less effective than we hoped" doesn't mean "not effective". As overall virus rates increase, the number of serious Covid-19 patients in hospitals has leveled off and new infections among the mostly-vaccinated over-60s are falling.