People with a history of significant allergic reactions should not receive the Covid vaccine, the medicines regulator has said, after two NHS workers experienced symptoms on Wednesday.
Both of the NHS staff carry adrenaline autoinjectors, suggesting they have suffered reactions in the past. These kind of devices, of which the best-known brand is the EpiPen, administer a swift adrenaline boost to counter allergic reactions that occur when some people, for instance, eat nuts.
The patient information leaflet with the Pfizer/BioNTech vaccine says it should not be given to people allergic to any substance in the vaccine, raising questions about the wisdom of NHS trusts selecting those staff members to be vaccinated.
“Signs of an allergic reaction may include itchy skin rash, shortness of breath and swelling of the face or tongue,” says the leaflet.
The identities of the NHS workers and hospitals where they were vaccinated have not been disclosed. NHS England confirmed the two incidents and said all trusts had now been advised not to give the jab to people with a history of allergic reaction.
Prof Stephen Powis, the national medical director for the NHS in England, said: “As is common with new vaccines, the MHRA [Medicines and Healthcare products Regulatory Agency] have advised on a precautionary basis that people with a significant history of allergic reactions do not receive this vaccination, after two people with a history of significant allergic reactions responded adversely yesterday. Both are recovering well.”
The MHRA advice states: “Any person with a history of a significant allergic reaction to a vaccine, medicine or food (such as previous history of anaphylactoid reaction or those who have been advised to carry an adrenaline autoinjector) should not receive the Pfizer/BioNtech vaccine. Resuscitation facilities should be available at all times for all vaccinations. Vaccination should only be carried out in facilities where resuscitation measures are available.”
The NHS workers are said to have developed symptoms of “anaphylactoid reaction” shortly after receiving the vaccine, and both have recovered after treatment.
Peter Openshaw, professor of experimental medicine at Imperial College London, said: “As with all food and medications, there is a very small chance of an allergic reaction to any vaccine. However, it is important that we put this risk in perspective. The occurrence of any allergic reaction was one of the factors monitored in the phase 3 clinical trial of this Pfizer/BioNTech Covid-19 vaccine, the detailed data from which was released yesterday. In this, they reported a very small number of allergic reactions in both the vaccine and placebo groups (0.63% and 0.51%).
“Similar to the rollout of all new vaccines and medications, this new Covid-19 vaccine is being monitored closely by the Medicines and Healthcare products Regulatory Agency. They will now investigate these cases in more detail to understand if the allergic reactions were linked to the vaccine or were incidental. The fact that we know so soon about these two allergic reactions and that the regulator has acted on this to issue precautionary advice shows that this monitoring system is working well.”
Stephen Evans, professor of pharmacoepidemiology at the London School of Hygiene and Tropical Medicine, said: “Allergic reaction occurs with quite a number of vaccines, and perhaps even more frequently with drugs. So it is not unexpected.
“The Pfizer data showed that about 0.6% of people had some form of allergic reaction in the trial on the vaccine, but about 0.5% on placebo. So there was a genuine excess of allergic reaction but this was small and the true rate is not known, and there is a lot of uncertainty around that estimate.
“The only thing that is contraindicated with this vaccine (meaning you mustn’t have it) is hypersensitivity to the vaccine or any of the excipients (other things in the vaccine), but some people won’t know if they have hypersensitivity to some constituents of the vaccine.
“What would be wise, as the MHRA have already advised, would be for anyone who has known severe allergic reaction such that they need to carry an EpiPen, to delay having a vaccination until the reason for the allergic reaction has been clarified.”