macrocephalopod

This is pretty incredible. Vaccine makers suggesting the change in U.K. policy on vaccine dose sequencing is potentially hugely flawed. Are we snatching defeat out of the jaws of victory?https://twitter.com/BenKentish/status/1344584306589638656 …

True that there is “no data” from their trial, but plenty of reasons to think that protection will last longer than 21 days based on (a) our understanding of the mechanism (b) experience with vaccines for other pathogens.

eg AstraZeneca vaccine *was* tested in a one dose regime and protection was as good (actually better) than two dose regime, up to the point they stopped the trial. Are there reasons to think that the Pfizer vaccine is different?

Pfizer is a 2 dose vaccine. In the trial some participants caught the virus between getting the first and second dose and one dose was found to be 52% effective.

Almost everyone who caught the virus after the first dose caught it within the first ten days, when you would not expect much if any immunity. Between 10 and 21 days it was nearly as effective as in the period following the second dose.

The difference is big. https://www.bmj.com/content/371/bmj.m4826 …

But as @macrocephalopod said - that’s all about timing. Those cases were in the short period after first dose and before we’d expect it to be working anyway. There’s no evidence about rates after would expect immunity.

What do you think we are taking about ... we are talking exactly about timing