> The MHRA has received 101 UK spontaneous adverse reactions associated with anaphylaxis or anaphylactoid reactions with the Pfizer/BioNTech vaccination. All patients have recovered from the anaphylaxis episode. 13 reports of anaphylaxis have been received for the COVID-19 Oxford University/AstraZeneca vaccine to date.
> As of 24 January, an estimated 5.4 million first doses of the Pfizer/BioNTech vaccine and 1.5 million doses of the Oxford University/AstraZeneca vaccine had been administered, and around 0.5 million second doses, mostly the Pfizer/BioNTech vaccine, had been administered.
For a rare disease, this would be pushing the rate of side effects and risk that is acceptable. But you've got a huge risk of catching COVID, and COVID is many orders of magnitude more dangerous than the vaccine. At least for now: if COVID vaccination is required in the long term, vaccines may have to get better.
An issue here is that no one could risk the vaccine failing, with the limited time we had and the massive trial. In a normal process, it's likely that smaller doses would have been selected. But here it looks like both Pfizer and Moderna "rounded up" a bit from what phase 2 trials pointed to as doses. If I were in charge, I'd have funded a non-inferiority trial in December for 1/3rd dose, which would put us in a position in February-March to massively stretch supplies and reduce side effects.