Information about allergy history and vaccine composition to support questions about suitability for vaccination with Comirnaty (Pfizer-BioNTech)

Allergies or intolerances

Individuals with allergies or intolerances may ask for advice about their suitability for Comirnaty COVID-19 vaccine. In order to decide on the correct action, take a full allergy history including details of the nature of previous reaction(s) and determine if the reaction was likely or potentially a:

  • reaction to Comirnaty or other COVID-19 vaccine
  • reaction to an excipient in the Comirnaty vaccine
  • reaction to something else (another allergen)

Reaction to a COVID-19 vaccine

Although the manufacturer of Comirnaty vaccines contraindicates use in those with a prior hypersensitivity to the active substance or to excipients in the vaccine, revaccination may still be possible and depends on the nature of the previous reaction.

Anaphylaxis

If the reaction was or might have been anaphylaxis, obtain expert advice (e.g. from an allergy specialist).

On the advice of an expert give a further dose of Comirnaty or give an alternative COVID-19 vaccine under medical supervision in a hospital setting. See the Green Book Chapter 14a: COVID-19 for further detail about setting, choice of vaccination, pre-medication and recommended observation period.

Non-anaphylactic reaction

Give a further dose of the same COVID-19 vaccine in any vaccination setting with special precautions. See the flow chart in the Green Book Chapter 14a: COVID-19 and accompanying text for guidance on action to take, suitable vaccinations, pre-medication and recommended observation periods dependent on the type and timing of prior reaction.

Reaction to an excipient in the Comirnaty vaccine

Comirnaty COVID-19 vaccines are contraindicated in those with a hypersensitivity to any excipient (ingredient) in the vaccine, but revaccination may be possible on the advice of an expert (e.g. allergy specialist). Allergy to any excipient is possible, but polyethylene glycol (PEG), contained in all Comirnaty vaccine preparations, is of particular importance. Excipients in each of the Comirnaty vaccines are listed in the summary of product characteristics (SmPCs), see links below:

Comirnaty 30 Concentrate for adults and adolescent vaccine

Comirnaty 10 Concentrate (for children 5-11 years) vaccine

Comirnaty Bivalent vaccine

PEG

Polyethylene glycols (PEGs), also known as macrogols, are a group of known allergens commonly found in medicines, many household products and cosmetics. Known allergy to PEG is rare and evidence now shows PEG allergy is implicated in only a minority of allergic reactions reported following COVID-19 vaccines. The Green Book Chapter 14a: COVID-19 suggests individuals with a known or suspected PEG allergy should be referred to an expert (e.g. allergy specialist) for advice.

On the advice of an expert give a further dose of Comirnaty COVID-19 vaccine under medical supervision in a hospital. Or as an alternative, a non-mRNA COVID-19 vaccine such as Novavax, which does not contain PEG, may be given in a setting with full resuscitation facilities (e.g. hospital). For detailed information, including information on recommended observation periods and pre-medication see the Green Book Chapter 14a: COVID-19.

Reaction to other allergen(s)

Providing the individual does not have an allergy to a COVID-19 vaccine or an excipient (ingredient) in the vaccine proceed with vaccination. The Green Book Chapter 14a: COVID-19 (table 5) recommends individuals with a previous allergic reaction (including anaphylaxis) to a food, insect sting and most medicines (where the trigger has been identified) can be vaccinated in any setting with no special precautions. However, some patients may be reassured by being observed for 15 minutes post vaccination or being pre-treated with an antihistamine.

The following information may be used to reassure individuals with specific allergies, intolerances, dietary considerations or religious beliefs:

Egg

Information from the manufacturer states egg is not used during the manufacturing of the vaccine and the final product does not contain egg. 

However, the manufacturer cannot guarantee that minute amounts of substances, such as egg, are not contained in raw materials obtained from their suppliers. 

Gluten

Information from the manufacturer states gluten is not used during vaccine manufacture and the final product does not contain gluten.

However, the manufacturer cannot guarantee that minute amounts of substances, such as gluten, are not contained in raw materials from their suppliers. 

Nut/soy

The SmPCs for Comirnaty vaccines do not list presence of nuts/soy.

However, the manufacturer cannot guarantee that minute amounts of substances, such as nuts/soy, are not contained in raw materials from their suppliers. 

Thiomersal

Comirnaty vaccines are preservative free and so do not contain thiomersal.  

However, the manufacturer cannot guarantee that minute amounts of substances, such as thiomersal, are not contained in raw materials from their suppliers.

Latex

UKHSA Covid-19 vaccination: information for practitioners states the rubber stopper of each multidose vial of Comirnaty vaccine consists of bromobutyl (a synthetic rubber) and does not contain latex.  In addition, information from the manufacture  confirms latex is not used as a raw material during the routine manufacturing process or as an excipient during vaccine formulation.

However, the manufacturer cannot guarantee that minute amounts of latex are not contained in raw materials obtained from their suppliers and cannot guarantee that the product has not come into contact with latex during the manufacturing process.

Religious or dietary considerations

Individuals may have questions about their suitability for vaccination based on religious beliefs or dietary considerations.

Use the following information, in conjunction with information from the reaction to other allergen(s) section and SmPCs for Comirnaty vaccines to support individuals with queries.

Animal- or human-derived vaccine content

The manufacturer (of all Comirnaty COVID-19 vaccines) states:

  • no excipients of animal or human origin are used in the finished product for Comirnaty 30, Comirnaty 10 or Comirnaty Bivalent
  • all lipid excipients used in the vaccine are either from plant-derived sources or are synthetic and have no animal components
  • a material used in the early stage of the manufacturing process of Comirnaty vaccines contains a component derived from bovine milk. The bovine milk is fit for human consumption and complies with bovine spongiform encephalopathy (BSE)/transmissible spongiform encephalopathies (TSE) regulations
  • other raw materials used in the manufacture of the vaccine are of non-animal origin
  • they cannot guarantee that minute amounts of substances are not contained in raw materials obtained from their suppliers

Jewish community

There is no information on Kosher certification for Comirnaty vaccines.

However, the Conference of European Rabbis released a position statement to support vaccination.

Muslim community

There is no information on Halal certification for Comirnaty vaccines.

However, the British Islamic Medical Association released a position statement to support vaccination.

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Update history

  1. Content from Pfizer allergy page and religions and dietary belief page updated, reformatted and merged to create one article.
  2. Published