Thread by @megtirrell

This appears to be an explainer of a change that happened in Pfizer's #covid19 vaccine supply expectations between Sept. 9 and Nov. 9, which flew under the radar because Pfizer reduced the 2020 supply expectation in the same release it reported 90% efficacy for the vaccine (1)

https://twitter.com/lisamjarvis/status/1334599858221674502

In Aug & Sept, Pfizer was forecasting up to 100m doses of its #covid19 vaccine by the end of 2020, and up to 1.3B doses by the end of 2021: (2)

Nov 9, when Pfizer reported its first phase 3 efficacy data, it included the new (reduced) forecast for supply: (Link here bc the dateline isn’t visible in this photo: pfizer.com/news/press-rel…) (3)

Pfizer notes there are several factors that affected doses estimated to be available in 2020:
-scaling up a vaccine at this pace is unprecedented
-scale of raw material supply chain took longer than expected
-outcome of clinical trial was later than initial projection (4)

Pfizer: “Modifications to our full scale production lines in the US and Europe are now complete and finished doses are being made at a rapid pace. We are confident in our ability to supply at a pace of approximately 1.3B doses by the end of 2021.”

Also confirmed 50m in 2020 (5)

And Operation Warp Speed’s Dr Moncef Slaoui confirms no change to expected US supply of Pfizer vaccine:

“There is NO change to their commitments to the US and I haven’t been informed of any issues.”

To summarize: Pfizer vaccine supply expectation remains the same now as Nov 9.