Advising individuals with allergies on their suitability for COVID-19 Vaccine Pfizer-BioNTech

Ashley Marsden, Senior Medicines Optimisation Pharmacist, Pharmacy Practice Unit, Royal Liverpool HospitalPublished Last updated See all updates

Advice on whether people with a previous allergic reaction can have the COVID-19 Vaccine Pfizer-BioNTech (Comirnaty).

Background

Individuals due to be vaccinated may have had previous allergies, and may ask their healthcare professional for advice on their suitability for vaccination.

Public Health England’s Immunisation Against Infectious Disease (the Green book) states that:

  • those with allergies, including prior anaphylaxis, to a food, insect sting or most medicines (where the trigger has been identified), can proceed with vaccination as normal according to local guidelines, as long as they are not known to be allergic to any component (excipient) of the vaccine;
  • anyone with a family history of allergies, a previous non-systemic reaction to a vaccine, hypersensitivity to non-steroidal anti-inflammatory drugs (e.g. aspirin, ibuprofen) or mastocytosis can proceed with vaccination as normal, according to local guidelines.

Below is a summary of knowledge about suitability for vaccination based on previous allergy status.

First dose of COVID-19 vaccine allergy

Only a very small number of individuals have experienced anaphylaxis when receiving a COVID-19 vaccine. Allergy to a previous dose of Pfizer-BioNTech COVID-19 vaccine or any of its components (excipients) may affect suitability.

Previous allergic reaction to a component of Pfizer-BioNTech vaccine

Public Health England’s Immunisation Against Infectious Disease (the Green book) provides the following information:

  • individuals with a history of allergic reaction to any component of the Pfizer-BioNTech vaccine e.g. polyethylene glycol should not receive it (except with expert advice).
  • If recommended by an expert Pfizer-BioNTech vaccine can be given under medical supervision in a hospital setting with full resuscitation facilities. A 30 minute observation period is recommended. Published data now show that some individuals with prior allergic reaction to PEG-containing medicines can tolerate the Pfizer-BioNTech vaccine.
  • If an expert recommends an alternative mRNA vaccine (i.e. Moderna) this can be given under medical supervision in a hospital setting with full resuscitation facilities. A 30 minute observation period is recommended.

Previous reaction to Pfizer-BioNTech vaccine

Public Health England’s Immunisation Against Infectious Disease (the Green book) provides the following information:

  • for individuals with a previous systemic anaphylaxis reaction to Pfizer-BioNTech vaccine seek advice from an allergy specialist. Many individuals do not react when given a dose of the same vaccine. A further dose of Pfizer-BioNTech vaccine can be considered if recommended by an expert, but this dose must be given under medical supervision in a hospital setting with full resuscitation facilities. A 30 minute observation period is recommended.
  • for individuals without any objective signs of anaphylaxis and for whom symptoms rapidly resolved (with no more than 1 dose of IM adrenaline), a further dose of Pfizer-BioNTech vaccine can be given in any vaccination setting.
  • individuals with non-allergic reactions (vasovagal episodes, non-urticarial skin reaction or non-specific symptoms) can receive further doses of Pfizer-BioNTech vaccine in any vaccination setting.

Our decision tool below will guide you through treating patients with prior allergy.

COVID-19 Vaccine Prior Allergy Decision Tool

Advice end-points

Seek advice from Allergy Specialist

If no respiratory or cardiovascular compromise, and symptoms rapidly resolved with a maximum of ONE dose of IM adrenaline, individuals can receive a further dose of the SAME vaccine in any care setting.

Observe for at least 30 minutes and consider pre-treatment with a dose of non-sedating antihistamine at least 30 minutes before vaccination.

Note that pre-treatment with antihistamines may mask initial symptoms of a reaction.

Individuals can receive a further dose of the SAME vaccine in any care setting. Consider pre-treatment with a dose of non-sedating antihistamine at least 30 minutes before vaccination.

Note that pre-treatment with antihistamines may mask initial symptoms of a reaction.

Individuals can receive a further dose of the SAME vaccine in any care setting. Consider pre-treatment with a dose of non-sedating antihistamine at least 30 minutes before vaccination.

Note that pre-treatment with antihistamines may mask initial symptoms of a reaction.

(Anaphylaxis, i.e. objective respiratory and/or cardiovascular compromise, usually with skin signs)

Seek advice from Allergy Specialist.

They will provide advice as to whether the patient can be revaccinated with the same vaccine or an alternative vaccine.

Please see individual vaccine articles for further information.

Excipients

Allergy due to any excipient is possible but polyethylene glycol is of particular importance. The manufacturer’s information states that a hypersensitivity to any of the excipients is a contraindication to the vaccine use.

Excipients present

The excipients listed in the manufacturer’s information are as follows:

  • ALC-0315 = ((4-hydroxybutyl) azanediyl)bis (hexane-6,1-diyl)bis(2-hexyldecanoate)
  • ALC-0159 = 2-[(polyethylene glycol)-2000]-N,N-ditetradecylacetamide
  • DSPC = 1,2-Distearoyl-sn-glycero-3-phosphocholine
  • cholesterol
  • potassium chloride
  • potassium dihydrogen phosphate
  • sodium chloride
  • disodium phosphate dihydrate
  • sucrose
  • water for injections

Polyethylene glycol (PEG) allergy

Polyethylene glycol (PEG – also known as macrogols) is a known allergen commonly found in medicines and also in household goods and cosmetics.

Since the Pfizer-BioNTech COVID-19 vaccine contains PEG, use in individuals with PEG allergy is contra-indicated according to the manufacturer’s information. Public Health England’s Immunisation Against Infectious Disease (the Green Book) advises that individuals who have had a prior allergic reaction to PEG should be referred to an allergist prior to vaccination.

The Green Book advises that a known allergy to PEG rare. But, undiagnosed PEG allergy should be considered in individuals with:

  • a history of idiopathic anaphylaxis
  • a history of immediate anaphylaxis to multiple, different drug classes, with the trigger unidentified
  • a history of anaphylaxis to a vaccine, injected antibody preparation of a medicine likely to contain PEG (e.g. depot steroid injection, laxative)

Managing patients with known or possible PEG allergy

Seek advice of an allergy specialist as recommended by the Green Book.

Guidance if allergy specialist recommends vaccination

The Green Book advises Pfizer-BioNTech should be administered in a setting with full resuscitation facilities (e.g. a hospital). A 30 minute observation period is recommended; some patients may benefit from pre-treatment with antihistamine – however, be aware that this may mask initial symptoms of a reaction.

Evidence to support vaccination

The Green Book advises that published data now show that some individuals with prior allergic reaction to PEG-containing medicines (e.g. PEG-asparaginase) can tolerate the PfizerBioNTech vaccine (although the historical reaction may have been due to a non-PEG component).

Considering AstraZeneca vaccine as an alternative

The Green Book  advises that AstraZeneca vaccine can be used as an alternative vaccine (unless otherwise contraindicated) for individuals with known or possible PEG allergies. The vaccine should be administered in a setting with full resuscitation facilities (e.g. a hospital), and a 30 minute observation period is recommended. Some patients may benefit from pre-treatment with antihistamine – however, be aware that this may mask initial symptoms of a reaction.

The rate of anaphylaxis reported to date after AstraZeneca vaccine is in line with the expected rate of anaphylaxis to non-COVID vaccines. The AstraZeneca vaccine does not contain PEG but does contain a related compound called polysorbate 80. Rarely, people with PEG allergy may also be allergic to polysorbate 80. However, polysorbate 80 is widely used in medicines and foods, and is present in many medicines including monoclonal antibody preparations. Some injected influenza vaccines (including the main vaccine used in over 65 year olds) contain polysorbate 80. Individuals who have tolerated injections that contain polysorbate 80 (including the adjuvanted influenza vaccine, Fluad® and the GlaxoSmithKline vaccine Fluarix®) are likely to tolerate the AstraZeneca vaccine.

Medicines allergy

Public Health England’s Immunisation Against Infectious Disease (the Green book) states that individuals with previous allergy to a medicine (where the trigger has been identified), including anaphylaxis, can receive the Pfizer-BioNTech COVID-19 vaccine. People with hypersensitivity to nonsteroidal antiinflammatory drugs e.g. aspirin, ibuprofen can also receive the Pfizer-BioNTech COVID-19 vaccine. However, the Green Book also states that PEG allergy should be considered in the following individuals (see also ‘PEG allergy’ section above).

  • those with a history of immediate anaphylaxis to multiple, different drug classes with the trigger unidentified.
  • those with a history of anaphylaxis to a vaccine, an injected antibody preparation or a medicine likely to contain PEG (e.g. depot steroid injection, laxative)
  • a history of idiopathic anaphylaxis

Seek allergy specialist advice regarding PEG allergy if needed (see ‘PEG allergy’ section for further detail)

See also the UK Chemotherapy board Clinician Frequently Asked Questions (FAQs) and guidance on COVID-19 vaccine for patients receiving Systemic Anti-Cancer Therapy (May 2021).  This has been produced in response to questions about use of COVID-19 vaccines in patients who have experienced a reaction to systemic anti-cancer therapy (SACT) or excipients of SACT.

The Children’s Cancer and Leukaemia group have produced advice for children who may be receiving PEG containing drugs.

Antibiotics

Public Health England’s Immunisation Against Infectious Disease (the Green book) states that individuals with previous allergy to a medicine (where the trigger has been identified), including anaphylaxis, can receive the Pfizer-BioNTech COVID-19 vaccine. Information from the manufacturer about antibiotic content states that:

  • Kanamycin is used during the manufacturing process of one of the raw materials used in the vaccine production; however it is not expected to be in detectable quantities in the final product presentation.
  • No other antibiotics (such as penicillins, sulphonamides and neomycin) are used during the manufacturing process.
  • They cannot guarantee that minute amounts of substances are not contained in raw materials obtained from their suppliers.

“Sulfa” medicines

Public Health England’s Immunisation Against Infectious Disease (the Green book) states that individuals with previous allergy to a medicine (where the trigger has been identified), including anaphylaxis, can receive the Pfizer-BioNTech COVID-19 vaccine.

Information from the manufacturer states that sulphonamide antibiotics are not used in the manufacturing process of the Pfizer-BioNTech COVID-19 vaccine. Additionally, there are no non-antibiotic “sulfa” drugs listed as an excipient in section 6.1 of the manufacturer’s information.

Other allergy considerations

As well as allergy considerations associated with previous vaccination and to excipients, other considerations are as follows.

Foods

Previous allergy to foods is covered in Public Health England’s Immunisation Against Infectious Disease (the Green book) which states that individuals with previous allergy to food, including anaphylaxis, can receive the Pfizer-BioNTech COVID-19 vaccine.

Information from the manufacturer states that the Pfizer-BioNTechCOVID-19 vaccine does not contain:

  • Egg
  • Gluten
  • Nuts
  • Soy

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

Latex

Our view is that the risks associated with previous latex allergy are low. The vaccine can be considered not to contain latex and poses the same minimal risk as other injectable medicines presented in vials with a bromobutyl rubber stopper.

This view is formed from:

  • Public Health England’s COVID-19 Vaccination Programme Information for Healthcare Professionals advice that the rubber stopper of each multidose vial of Pfizer-BioNTech vaccine consists of bromobutyl (a synthetic rubber), and does not contain latex.
  • Information from Pfizer Medical Information states that latex is not used as a raw material during the routine manufacturing process or as an excipient during vaccine formulation. (Although they 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.)
  • Information in The Green Book (chapter 6), which includes advice on managing vaccine choice in patients with severe (i.e. anaphylactic) allergy to latex, would categorise the Pfizer-BioNTech vaccine as not containing latex.

Patients with an allergy to latex can be directed to the Anaphylaxis Campaign website for information.

Thiomersal content

The Pfizer BioNTech COVID-19 vaccine does not contain thoimersal, according to the information for healthcare professionals.

Summary of allergy considerations

The table below is a pictorial summary of the management of patients with a history of allergy, reproduced with kind permission from authors of Public Health England’s Immunisation Against Infectious Disease (the Green book).

Also of interest

Managing anaphylaxis in the COVID-19 vaccination setting

Advice on managing anaphylaxis in the vaccination setting with specific reference to COVID-19 vaccines.

Change history

  1. Page, tool and image updated to reflect changes in green book regarding management of those with prior allergy to vaccine and PEG. Links updated.
  1. Changes reflect availability of licensed product Comirnaty.
  1. PEG and polysorbate 80 sections updated and editorial changes made.
  1. Addition of COVID-19 Vaccine Prior Allergy Decision Tool and made other editorial changes.
  1. Changed 'First dose of Pfizer-BioNTech COVID-19 vaccine or other medicines allergy' heading to 'First dose of Pfizer-BioNTech COVID-19 vaccine allergy'.
  2. Removed 'Individuals with a history of immediate onset-anaphylaxis to multiple classes of drugs or an unexplained anaphylaxis should not be vaccinated with the Pfizer-BioNTech vaccine, except on the advice of an allergy specialist. The AstraZeneca vaccine can be used as an alternative (if not otherwise contraindicated), particularly if they previously tolerated an injected influenza vaccine. The vaccine should be administered in a setting with full resuscitation facilities (e.g. a hospital), and a 30 minute observation period is recommended' from 'First dose of Pfizer-BioNTech COVID-19 vaccine allergy' section as it is also in the PEG section.
  1. Link added to the UK Chemotherapy board Clinician Frequently Asked Questions (FAQs) and guidance on COVID-19 vaccine for patients receiving Systemic Anti-Cancer Therapy in 'other drugs' section.
  2. Removed the statement in the polysorbate 80 allergy section that individuals with confirmed polysorbate 80 allergy should discuss this with an allergy specialist/ immunologist before receiving the Pfizer-BioNTech COVID-19 vaccine, as the the BSACI COVID-19 Vaccinations and Allergies FAQ no longer states this.
  1. Information on prior allergy common to all vaccines moved the main page covering common allergy points
  1. Added "Flowchart for managing patients who have allergic reactions to the first dose of COVID-19 vaccine" to "First dose of AstraZeneca COVID-19 vaccine or other medicines allergy" section; added a new section "Summary of allergy considerations", including a summary table.
  1. Updated to reflect changes in the Green Book: "Background" section updated; "First dose of Pfizer-BioNTech COVID-19 vaccine or other medicines allergy" section updated, including addition of BSACI management advice for people who had a reaction to the first dose of vaccine; significant updates to "Polyethylene glycol (PEG) allergy" section; added which patients should be discussed with an allergy specialist prior to vaccination in the "other drugs" section.
  1. Changes made to include page as part of a series covering similar topics
  2. Changes made to clarify advice in relation to allergies and excipients
  3. Changes made to clarify advice in relation to other allergy considerations, including addition of advice regarding latex
  1. Added link to BSACI in PEG/polysorbate 80 section
  1. Polysorbate 80 information added.
  1. PEG section modified, based on updated information from the Green Book.
  1. Published