NHS England sent an email to medical directors last night warning of allergic reactions to Pfizer vaccine after 2 NHS staff with a history of allergies suffered reactions yesterday - MHRA has said no one with allergy history will now get the vaccine https://www.independent.co.uk/news/health/covid-vaccine-allergic-reactions-uk-b1768530.html

Both staff carried adrenaline injectors and recovered after treatment, the email said. The restrictions are a precaution. Thousands of people were vaccinated yesterday.

Dr June Raine, chief executive of the MHRA, said the regulatory body was examining the allergic reactions: "We know from the very extensive clinical trials this wasn’t a feature."

Some more info:

Interestingly - it looks like people with a history of severe allergic reactions were left out of Pfizer's clinical trials: https://pfe-pfizercom-d8-prod.s3.amazonaws.com/2020-09/C4591001_Clinical_Protocol.pdf