COVID-19 vaccine contraindications and precautions

Contraindications

Pfizer and Moderna COVID-19 vaccines

A contraindication to one mRNA COVID-19 vaccine should be considered a contraindication to other COVID-19 vaccines made with that vaccine platform. For example, a person who is contraindicated for any Pfizer COVID-19 vaccine would also be contraindicated for any Moderna COVID-19 vaccine.

Contraindications to original and bivalent formulations of both Pfizer and Moderna are:

• anaphylaxis to a previous dose of an mRNA COVID-19 vaccine (Pfizer or Moderna)
• anaphylaxis to any component of the vaccine, including polyethylene glycol (PEG)
• any other serious adverse event attributed to a previous dose of Pfizer or Moderna (and without another cause identified) that has been:
  • reported to state adverse event reporting programs and/or the TGA
  • AND has been determined following review by, and/or on the opinion of, an experienced immunisation provider/medical specialist to be a contraindication to future doses, taking into account whether repeat vaccine doses would be associated with a risk of recurrence of the serious adverse event.

Novavax

Contraindications to Novavax are:

• anaphylaxis after a previous dose
• anaphylaxis to any component of the vaccine, including polysorbate 80
• any other serious adverse event attributed to a previous dose of Novavax (and without another cause identified) that has been:
  • reported to state adverse event reporting programs and/or the TGA
  • AND has been determined following review by, and/or on the opinion of, an experienced immunisation provider/medical specialist to be a contraindication to future doses, taking into account whether repeat vaccine doses would be associated with a risk of recurrence of the serious adverse event.

Assessment of vaccine-attributable adverse events

Assessment of adverse events following immunisation requires detailed information about the event and the severity of the condition, as well as a determination of the likelihood of a causal link with vaccination. Serious adverse events are generally defined as those which:

• require hospitalisation
• are medically significant (for example, immune thrombocytopenia purpura, myocarditis)
• are potentially life-threatening (for example, anaphylaxis), and/or
• result in persistent or significant disability (for example, Guillain-Barré syndrome).

These reactions do not typically include expected local or systemic reactions that are known to occur within the first few days after vaccination. Attributing a serious adverse event to a previous dose of a COVID-19 vaccine may require discussion with the person’s GP, local immunisation service or relevant medical specialist.

Anaphylaxis after COVID-19 vaccines

Anaphylaxis after COVID-19 vaccines is rare and occurs at a similar rate to other common vaccines. In a study that included original formulations of Pfizer, Moderna and AstraZeneca vaccines the overall rate of anaphylaxis was around 10 per million doses. The rate of anaphylaxis after Novavax is not yet known.¹

Precautions

Specific allergies

The following people should be assessed to check they are suitable for vaccination:

• people with immediate (within 4 hours) and generalised symptoms of a possible allergic reaction (such as urticaria/hives) to a previous dose of a COVID-19 vaccine, without anaphylaxis
• people with a generalised allergic reaction (without anaphylaxis) to any component of the COVID-19 vaccine to be administered (such as PEG in Pfizer and Moderna, or polysorbate 80 in Novavax)
• people with a history of anaphylaxis to previous vaccines or multiple drugs (injectable or oral) where a component such as PEG (for mRNA vaccines) or polysorbate 80 (for Novavax) may be the cause
• people with a history of confirmed mastocytosis with recurrent anaphylaxis that requires treatment.

Assessment may be done in consultation with an allergist/immunologist or specialist immunisation clinic.

People in these categories may need one or more of the following:

• to be vaccinated in a facility with medical staff in attendance
• to be observed for at least 30 minutes following administration of a COVID-19 vaccine dose
• to be vaccinated with an alternative brand of COVID-19 vaccine.

See ASCIA Guide: Allergy and COVID-19 Vaccination for more information.

People with a suspected allergy to a previous dose

People who are suspected to have had an allergic reaction to their first dose of a COVID-19 vaccine should seek advice from the state/territory specialist immunisation service or a specialist allergist/immunologist. These people may need a clinical assessment before the second vaccine dose.

Before and during each vaccination session, check that up-to-date protocols, equipment, medicines and trained staff to manage anaphylaxis are available.

See the Preparing for vaccination section of the Australian Immunisation Handbook.

People with other allergies

All people receiving a vaccine should be observed for at least 15 minutes at the clinic after administration. No additional precautions are needed for people with:

• a history of allergy
• anaphylaxis to food, drugs, venom or latex
• allergic conditions, including asthma, atopic dermatitis (eczema) or allergic rhinitis (hay fever).

This is in accordance with the current recommendations in the Australian Immunisation Handbook. It is important that all providers are trained in anaphylaxis management.

Cardiac precautions

People with a history of any of the following conditions can receive a COVID-19 vaccine. But advice should be sought from a GP, immunisation specialist or cardiologist about the best timing of vaccination and whether any additional precautions are recommended:

• recent (within the past 3 months) myocarditis or pericarditis
• acute rheumatic fever or acute rheumatic heart disease (with active myocardial inflammation) 
• acute decompensated heart failure.

People who develop myocarditis and/or pericarditis after a COVID-19 vaccine should defer further doses and discuss options for further COVID-19 vaccination with their treating doctor.

For more details, see the Joint ATAGI-CSANZ Guidance on Myocarditis and/or Pericarditis after COVID-19 Vaccines.

Capillary leak syndrome

People with a history of capillary leak syndrome should consider a brand other than Moderna. A few cases of capillary leak syndrome flare-up have been reported after vaccination with the original formulation of Moderna.

Acute illness

Defer vaccination in people with an acute illness. This includes febrile illness (axillary temperature ≥38.5°C). This is a general precaution for all vaccines to avoid potentially attributing symptoms of the acute illness to the vaccine, or attributing adverse effects from the vaccine to the acute illness.

People with bleeding disorders

People with bleeding disorders and people who are receiving anticoagulant therapy may develop haematomas at intramuscular injection sites. Inform the person about this risk before vaccination.  

Pfizer, Moderna and Novavax should only be administered by intramuscular injection.

To administer an intramuscular injection to a person with a bleeding disorder:²

• use a 23 or 25 gauge needle
• apply firm pressure to the injection site without rubbing for at least 2 minutes after injection.

For more details on how to safely administer vaccines intramuscularly to people with bleeding disorders, refer to the Vaccination for people with bleeding disorders section in the Australian Immunisation Handbook.

Subcutaneous administration is not recommended, as no data are available on the safety or immunogenicity of COVID-19 vaccines given via this route.

Further reading

1. Maltezou H, Anastassopoulou C, Hatziantonious S, Poland G, Tsakris A. Anaphylaxis rates associated with COVID-19 vaccines are comparable to those of other vaccines. Vaccine 2022;40:183-6.
2. National Center for Immunization and Respiratory Diseases. General recommendations on immunization --- recommendations of the Advisory Committee on Immunization Practices (ACIP). MMWR Recommendations and Reports 2011;60:1-64.