A number of people have asked me for my thoughts on today’s vaccine news, so here goes… (CAVEAT: I am NOT an epidemiologist, just someone with an occupational interest from a previous life) #vaccine

1. These are interim results, based on 94 confirmed Covid-19 cases out of 43,538 participants. We need to wait until the trial reaches 164 confirmed cases before we have more reliable confirmation. But nonetheless, it’s hugely promising and better than most people expected.

2. These results indicate 90% efficacy among people who *took the vaccine*. For an immunisation programme to be fully effective, it will need mass take-up. Never has tackling anti-vax propaganda been more important, and it’s a more difficult challenge than people appreciate.

3. It will also take time to determine the longer-term efficacy and safety – Pfizer has today said it will be evaluating efficacy based on cases accruing 14 days after the second dose as well (subject to FDA approval). How long any protection lasts is a crucial question.

4. This virus affects people differently, and it is yet to be seen exactly how effective the vaccine is at preventing severe cases, which are more likely to lead to hospitalisation and death. Will be interesting to see the age/risk profile of the 94 cases, and how they split

5. Rolling out the vaccine will require the biggest logistical effort since WW2 (esp. given the cold chain and need for multiple doses) – government has been doing lots of groundwork to get things ready for a working vaccine, but it will still take many months to roll out fully

6. These caveats aside (and the data still needs to be peer-reviewed), this is hugely promising news – and all the more impressive given this is a vaccine for a novel virus that did not exist twelve months ago.

7. Particularly encouragingly, the strong results from the Pfizer vaccine increase the probability of success of other COVID-19 candidates that use a "spike protein" approach (like the Oxford-AstraZeneca vaccine).

8. Final thought: if findings verified, govt faces a thorny political challenge: namely, what is the risk appetite for reopening the economy ahead of the vaccine? Last thing ministers will want to do is move too fast and risk an unnecessary third wave when the end is in sight...