Background

Hypersensitivity/allergic reactions following immunisation can be classified as:

  • Urticarial – a red, itchy skin rash often referred to as hives, which characteristically has a central raised white wheal surrounded by an area of redness
  • Non-urticarial rash – skin changes that don’t involve hives
  • Angioedema – swelling in the deeper layers of the skin
  • Generalised allergic reaction – involving symptoms like vomiting and diarrhoea
  • Anaphylaxis – a sudden onset and rapid progression of symptoms involving the skin, as well as systemic symptoms respiratory and/or cardiovascular systems

Suspected hypersensitivity reactions, particularly non-urticarial skin rashes following immunisation, are common, however true vaccine allergy, where a person is contraindicated from being immunised with the same vaccine in the future, is rare (in most studies reported as less than 1 case per million doses)

Post-licensure surveillance of COVID-19 vaccines show anaphylaxis following administration of COVID-19 AstraZeneca occurring at similar rates to routine vaccines [refer to TGA: AstraZeneca ChAdOx1-S COVID-19 vaccine].  Anaphylaxis following Comirnaty™ (Pfizer/BioNTech), whilst still extremely rare, occurs at a slightly higher rate of approximately 4.7 cases per million doses.

A confirmed vaccine allergy usually requires a specialist consultation with a vaccine allergy specialist, often with specific testing or a vaccine challenge under supervision.

All COVID-19 immunisation hypersensitivity/allergic reactions should be reported to your state’s vaccine safety reporting service. In Victoria this is SAEFVIC. SAEFVIC staff may direct the report to an Immunisation Specialist or alternatively to a Vaccine Allergy Specialist within the VicSIS network (a network of specialist immunisation clinics in Victoria), as appropriate.

Allergy to components of COVID-19 vaccines

Polyethylene Glycol (PEG)

PEG is an ingredient contained in Comirnaty™. It is also a commonly used ingredient of other medications, hand sanitisers, cosmetics, bathroom products and colonoscopy preparation products, routinely used within Australia. Whilst it is uncertain whether PEG contained in mRNA vaccines may trigger anaphylaxis, additional precautions are required prior to administration.

It is recommended people with a history of confirmed or suspected allergy to PEG seek specialist advice from an immunology/allergy/vaccination specialist regarding the safety of receiving an mRNA COVID-19 vaccine.

NB: Vaccination with the Comirnaty™ COVID-19 vaccine is contraindicated in people with documented anaphylaxis to PEG.

Polysorbate 80

Polysorbate 80 is chemically related to Polyethylene Glycol and is an ingredient in COVID-19 AstraZeneca vaccine.

If there is a history of confirmed or suspected allergy to Polysorbate 80 it is recommended that specialist advice be sought from an immunology/allergy/vaccination specialist regarding the safety of administering COVID-19 AstraZeneca.

NB: Vaccination with the COVID-19 AstraZeneca vaccine is contraindicated in people with documented anaphylaxis to Polysorbate 80.

Latex

The COVID-19 vaccines with provisional registration for use within Australia (Comirnaty™ and COVID-19 AstraZeneca vaccine) can both be administered to people with latex allergies following standard precautions, with a 15-minute post-vaccination observation period. Neither Comirnaty™ or COVID-19 AstraZeneca vials contain latex.

COVID-19 vaccines and allergies

Reaction following a previous dose of a COVID-19 vaccine

The only two absolute contraindications to vaccination are anaphylaxis to a previous dose of the same vaccine or anaphylaxis to a component of the vaccine.

Additional precautions are recommended for individuals with possible allergic reactions to a previous dose of a COVID-19 vaccine. In this instance, a specialist review by an immunology/allergy/vaccination specialist to undertake a risk/benefit assessment to assess suitability for further vaccination should be undertaken.

If an individual experiences anaphylaxis after being vaccinated with one type of COVID-19 vaccine, this does not preclude them from having another type following the additional precautions above. If there is a high risk of an allergic reaction to one of the COVID-19 vaccines due to an existing allergy to PEG or Polysorbate 80 it may be possible to a have a COVID-19 vaccine that does not contain the ingredient, depending on availability and with appropriate medical advice.

COVID-19 vaccination in people with allergic conditions

For patients with a history of anaphylaxis to food, drugs, venom or latex, it is recommended a routine observation period of 15 minutes following COVID-19 vaccination is observed.

If there is a history of a known systemic mast cell activation disorder with raised mast cell tryptase that has required treatment, additional precautions are recommended. Following consultation with an immunology/allergy/vaccination specialist to undertake a risk/benefit assessment to assess suitability for vaccination should be undertaken. Immunisation in a medical facility with a 30-minute observation period may be recommended.

Please refer to COVID-19 vaccination – ATAGI clinical guidance on COVID-19 Vaccine in Australia in 2021 or the ASCIA Allergy, Immunodeficiency, Autoimmunity and COVID-19 Vaccination Position Statement for more information.

Management following anaphylaxis to a COVID-19 vaccine

Should symptoms of anaphylaxis occur immediate treatment should be provided [refer to Australian Immunisation Handbook: Adverse events following immunisation]

Investigations

Tryptase levels are recommended following potential allergic reactions as they assist with allergy assessment. Normal tryptase levels are reassuring. Tryptase levels are recommended 1 hour, 4 hours and 24 hours post reaction, however, if this is not possible, it recommended once an individual presents to an emergency department and is stable and then just prior to discharge in the case of a short admission.

It is recommended that EpiPens only be prescribed by an allergy/immunology specialist following a review. This is based on the following:

  • Vaccines can be easily avoided and EpiPens are on the Pharmaceutical Benefits Scheme for indications that cannot be avoided
  • A prescription of an EpiPen has been shown to increase anxiety in people once it is prescribed even if it is not clinically indicated, which is thought to be due to the perceived uncertainty of future reactions.

Resources:

Authors: Rachael McGuire (MVEC Education Nurse Coordinator), Nigel Crawford (Director, SAEFVIC, Murdoch Children’s Research Institute), Daryl Cheng (Paediatrician, The Royal Children’s Hospital), Francesca Machingaifa (MVEC Education Nurse Coordinator), Sara Barnes (Head of Allergy, Monash Health) and Adele Harris (Research Nurse, SAEFVIC, Murdoch Children’s Research Institute)

Date: March 2021

Materials in this section are updated as new information and vaccines become available. The Melbourne Vaccine Education Centre (MVEC) staff regularly review materials for accuracy.

You should not consider the information in this site to be specific, professional medical advice for your personal health or for your family’s personal health. For medical concerns, including decisions about vaccinations, medications and other treatments, you should always consult a healthcare professional.