Covid Vaccine Allergy
This referral pathway is for patients with a history of allergic disease that raises concerns about receiving COVID vaccination.
COVID Vaccine Allergy Referral form
All referrals will be reviewed by the allergy department and advice and guidance will be provided as soon as possible to avoid unnecessary delays in receiving vaccination.
A very small number of individuals have experienced anaphylaxis when vaccinated with the Pfizer BioNTech vaccine. Following close national surveillance, the MHRA is clear that most people, including those with allergic disease, can be vaccinated. Anyone with a previous history of allergy to a Covid-19 vaccine or a relevant excipient, should avoid that vaccine. However, it may be possible to use an alternative vaccine.
All recipients of the Pfizer BioNTech, Novavax, and Moderna mRNA COVID-19 vaccines should be kept for observation and monitored for a minimum of 15 minutes. Facilities for management of anaphylaxis should be available at all vaccination sites.
Most recent advice in the Green Book is that:
- Individuals with undiagnosed PEG allergy often have a history of immediate onset-unexplained anaphylaxis or anaphylaxis to multiple classes of drugs.
PEG is a common excipient in medications, household products and cosmetics. Allergy to PEG is very rare and has only been implicated in a small proportion of Covid-19 vaccine allergies. Please review ingredient lists of patient’s tolerated medicines, as tolerance of PEG can often be demonstrated.
In those patients where PEG tolerance has not been demonstrated, they should not be vaccinated with Pfizer BioNTech or Moderna mRNA vaccines, except on the expert advice of an allergy specialist. AstraZeneca vaccine can be used as an alternative (if not otherwise contraindicated), particularly if they have 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.
- Individuals with an immediate localised urticarial (itchy) skin reaction (without systemic symptoms) or delayed urticaria/angioedema not requiring medical attention to the first dose of a COVID-19 vaccine should receive the second dose of the same vaccine with prolonged observation (30 minutes) in any vaccination setting: see flow chart on page 18 here.
- Individuals with non-allergic reactions (vasovagal episodes, non-urticarial skin reaction or non-specific symptoms) to the first dose of a COVID-19 vaccine can receive the second dose of vaccine in any vaccination setting.
Assessment
See referral form.
Regional COVID Vaccine Allergy Referral form – please ensure the form is completed as fully as possible. Failure to do so may result in the referral being returned and a delay in patient assessment.
All referrals without a Regional COVID Vaccine Allergy Referral form attached will be returned.
Please note these need to be sent by the referring clinician and not directly from the patient.
Red Flags
Patients that experience red flag symptoms should receive emergency management and be admitted to hospital via ambulance (even if symptoms have settled):
Amended criteria for the diagnosis of anaphylaxis, proposed by the WAO Anaphylaxis Committee, 2019.
Anaphylaxis is highly likely when any one of the following 2 criteria are fulfilled:
1. Acute onset of an illness (minutes to several hours) with involvement of the skin, mucosal tissue, or both (e.g., generalized hives, pruritus or flushing, swollen lips-tongue-uvula)
AND AT LEAST ONE OF THE FOLLOWING:
- Respiratory compromise (e.g., dyspnoea, wheeze-bronchospasm, stridor, reduced PEF, hypoxemia)
- Reduced BP or associated symptoms of end-organ dysfunction (e.g., hypotonia [collapse], syncope, incontinence
- Severe gastrointestinal symptoms (e.g., severe crampy abdominal pain, repetitive vomiting), especially after exposure to non-food allergens
2. Acute onset of hypotension* or bronchospasm or laryngeal involvement after exposure to a known or highly probable allergen for that patient (minutes to several hours), even in the absence of typical skin involvement.
PEF, Peak expiratory flow; BP, blood pressure.
*Hypotension defined as a decrease in systolic BP greater than 30% from that person's baseline, OR.
i. Infants and children under 10 years: systolic BP less than (70 mmHg + [2 x age in years])
ii. Adults: systolic BP less than <90 mmHg.
A Laryngeal symptoms include: stridor, vocal changes, odynophagia.
B An allergen is a substance (usually a protein) capable of triggering an immune response that can result in an allergic reaction. Most allergens act through an IgE-mediated pathway, but some non-allergen triggers can act independent of IgE (for example, via direct activation of mast cells).
C The majority of allergic reactions occur within 1–2 hours of exposure, and usually much quicker. Reactions may be delayed for some food allergens (e.g., alpha-gal) or in the context of immunotherapy, occurring up to 10 hours after ingestion.”
Investigations
Patients with suspected anaphylaxis reactions should have:
- Mast Cell Tryptase taken at least 24 hours after acute anaphylaxis, and also ideally during the reaction in line with RCUK and NICE anaphylaxis management guidelines (as soon as possible; and 1-2 hours but no later than 4 hours after onset of symptoms).
Management
The following groups of people can receive any of the available vaccines without prior allergy assessment:
- People with no history of allergy or anaphylaxis
- People with a history of non-allergic reactions (e.g., vasovagal episodes, non-urticarial skin reactions, non-specific symptoms)
- People with local skin reactions at the site of injection
(these individuals can have a second dose of the same vaccine in any setting with observation for 30 minutes; those with delay (>2h) in onset of symptoms can consider premedicating with a non-sedating antihistamine 30 minutes prior to vaccination)
- People with delayed-onset (>2 hours) symptoms following vaccination that didn’t require medical attention
- People with allergic diseases such as hayfever, eczema, or asthma
- People with spontaneous urticaria and angioedema, without features of anaphylaxis (these individuals can have a second dose of the same vaccine in any setting with observation for 30 minutes)
- People with a history of allergy or anaphylaxis to foods or venom
- People with a history of allergy or anaphylaxis to a single drug class (e.g., penicillins)
- People with a history of anaphylaxis to any non-COVID vaccine
(as long as they are not known to be allergic to any component (excipient) of the vaccine)
Details of the excipients of the vaccines can be found at the following links:
Referral
Referral Criteria
- Anaphylaxis following COVID vaccination
- Anaphylaxis to a COVID vaccine excipient (e.g. PEG, polysorbate 80)
- Anaphylaxis to multiple classes of drugs or vaccinations, where a tolerance of PEG cannot be established
- Anaphylaxis to biologic medications, where a tolerance of polysorbate 80 cannot be established
- Spontaneous or unexplained anaphylaxis
- People with delayed-onset (>2 hours) symptoms following vaccination that did require medical attention
Please refer to the RMS under the allergy specialty.
Regional COVID Vaccine Allergy Referral form – please ensure the form is completed as fully as possible. Failure to do so may result in the referral being returned and a delay in patient assessment.
All referrals without a Regional COVID Vaccine Allergy Referral form attached will be returned.
Please note these need to be sent by the referring clinician and not directly from the patient.
Supporting Information
GP Information:
Patient Information:
www.allergyuk.org(Allergy and the coronavirus (COVID-19) Vaccine)
Reference:
1. https://southwest.devonformularyguidance.nhs.uk/referral-guidance/covid-19/covid-vaccine-allergy
Review date: 17th January 2025
Next review date: 17th January 2027
Clinical Editor: Dr Kate Northridge
Contributors: Dr Catherine Elliott, Specialist Doctor in Allergy, University Hospital Plymouth