What type of vaccines are the Comirnaty (Pfizer) COVID-19 vaccines?

Comirnaty, also called BNT162b2 or tozinameran, is a COVID-19 vaccine developed by Pfizer and BioNTech. It is an mRNA vaccine that contains the genetic code for an important part of the COVID-19 virus called the 'spike protein'. After getting the injection, the body reads the genetic code and makes copies of the spike protein. The immune system then detects these spike proteins and learns how to recognise and fight against COVID-19. The genetic code is quickly broken down and cleared away by the body. 

Is there a difference between the two Comirnaty (Pfizer) COVID-19 vaccines?

Yes. The Comirnaty (Pfizer) 5 to <12 years of age formulation vaccine is a different formulation to the Comirnaty (Pfizer) adult/adolescent formulation vaccine.

The formulation for people 5 to <12 years of age has an orange cap and the dose is 10 micrograms in 0.2mL, while the formulation for people 12 years and over has a purple cap and contains 30 micrograms in 0.3mL. The required diluent is also a different volume. These two vaccines must always be managed as separate vaccines. Lower doses of the adult/adolescent formulation MUST NOT be administered to people aged 5 to <12 years of age.  

Please refer to the TGA Product Information (PI) for the most up to date information.

What are the most recent Australian Technical Advisory Group on Immunisation (ATAGI) recommendations in regard to the Comirnaty (Pfizer) 5 to <12 years of age formulation vaccine?

  • ATAGI recommends vaccination with the Comirnaty (Pfizer) 5 to <12 years of age formulation vaccine for all children aged 5 to <12 years of age.
  • Children aged 5 to <12 years of age with medical risk factors for severe illness, Aboriginal and Torres Strait Islander children, and children living in crowded conditions or outbreak areas are most likely to benefit from COVID-19 vaccination given their increased risk of severe outcomes and/or exposure.
  • Children aged 5 to <12 years of age who have previously had SARS-CoV-2 infection can receive the Comirnaty (Pfizer) 5 to <12 years of age COVID-19 vaccine. This is recommended following recovery from their illness or vaccination but can be deferred for up to 6 months. This includes children with a past history of PIMS-TS or post COVID-19 condition ('long COVID').

Is there any additional training required before administering the Comirnaty (Pfizer) 5 to <12 years of age formulation vaccine?

All health professionals involved in administering COVID-19 vaccines must have completed the Australian Government training on COVID-19 vaccines including the relevant modules for each vaccine they intend to administer. A specific module for the Comirnaty (Pfizer) 5 to <12 years of age formulation vaccine is now available.

The module provides information on the handling, storage and administration requirements for this vaccine.

Can children who have had SARS-CoV-2 receive a COVID-19 vaccine?

Children who have previously had SARS-CoV-2 infection can receive Comirnaty (Pfizer) 5 to <12 years of age formulation vaccine. Past infection reduces the risk of reinfection for at least 6 months. However, a two-dose primary schedule is recommended in previously infected people and is safe and well tolerated. People with SARS-CoV-2 infection can be vaccinated as soon as they have recovered from their acute illness or can defer vaccination for up to six months after onset of the SARS-CoV-2 infection. People who have received an anti-SARS-CoV-2 monoclonal antibody or convalescent plasma should defer future doses of COVID-19 vaccine for at least 90 days.

Can children receive one of the other available COVID-19 vaccines?

No. The Comirnaty (Pfizer) 5 to <12 years of age formulation vaccine is the only vaccine that has been provisionally approved by the Therapeutic Goods Administration (TGA) for use in children aged 5 to <12 years of age.

Can the current adult/adolescent formulation (purple cap) be used to vaccinate children aged 5 to less than 12 years of age?

No. A lower dose of the adult/adolescent formulation MUST NOT be administered to people aged 5 to <12 years of age. The Comirnaty (Pfizer) 5 to <12 years of age formulation vaccine is the only vaccine that has been provisionally approved by the Therapeutic Goods Administration (TGA) for use in children aged 5 to <12 years of age. 

Why can't I use the existing formulation, just at a lower dose?

The use of the current adult/adolescent formulation (purple cap) would result in an injection volume considered too small for effective delivery of the required dose. The Comirnaty (Pfizer) 5 to <12 years of age formulation vaccine (orange cap) is the only vaccine that has been provisionally approved for use in children aged 5 to <12 years of age by the Therapeutic Goods Administration (TGA). This approval is based on the results of clinical trials demonstrating that the vaccine is highly effective and that most side effects are mild and short-lived.

What should I do if the vaccine remaining in the vial cannot provide a full dose of 0.2mL?

The remaining excess volume and the vial should be discarded. Do NOT pool excess vaccine from multiple vials.

What if the multidose vial is frozen?

The multidose vial must be thawed prior to use. Frozen vials should be transferred to an environment of +2°C to +8°C to thaw; a 10 vial pack may take 4 hours to thaw. Additional information is available in the Therapeutic Goods Administration approved Product Information.

How long can unopened vials be stored at +2 to +8°C?

Unopened vials can be stored for up to 10 weeks at +20C to +8OC. Additional information is available in the Therapeutic Goods Administration approved Product Information.

Can I thaw individual vials of the Comirnaty (Pfizer) 5 to <12 years of age formulation vaccine (orange cap)?

Individual frozen vials may be thawed for 30 minutes at temperatures up to +300C for immediate use. Additional information is available in the Therapeutic Goods Administration approved Product Information.

What is the volume of diluent for the Comirnaty (Pfizer) 5 to <12 years of age formulation vaccine (orange cap)?

Thawed vaccine must be diluted in its original vial with 1.3mL of sodium chloride 9 mg/L (0.9%) solution (normal saline). Gently invert the diluted suspension 10 times. DO NOT shake. The diluted vaccine should present as a white to off-white suspension. Note the volume for the Comirnaty (Pfizer) 5 to <12 years of age formulation is different to the adolescent/adult formulation.

What should I do if the vial contains particles, or the vaccine is discolored?

Do NOT use the vial. Quarantine it in a refrigerator at +2°C to 8°C, clearly labelled "Do not use". Contact the Commonwealth Vaccine Operations Centre (VOC) for advice or on 1800 318 208.

How should I manage multiple vaccine brands and formulations?

The vaccines should be stored separately to avoid errors and incorrect administration.  If they must be stored together in the same fridge/freezer they must be stored in separate areas and be clearly labelled. Vaccines must never be in the same clinical area at the same time including the preparation area when drawing up. Further advice is available on the NSW Health webpage: Process for managing multiple COVID-19 vaccines at the same site.

What should I do if I inadvertently administer the incorrect dose or vaccine?

Advice must be sought from the Commonwealth Vaccine Operations Centre (VOC) for advice or on 1800 318 208.

Clinical advice is also available from the NSW Immunisation Specialist Immunisation Service via email at: SCHN-NSWISS@health.nsw.gov.au. Ensure that you include your name and contact details.

What is the recommended dosing schedule for people aged 5 to <12 years of age?

ATAGI recommends a dose interval of 8 weeks apart for children aged 5 to 11 years. ATAGI recommends a longer interval than the manufacturer’s recommended schedule of 2 doses, 3 weeks apart which is described in the product information.

ATAGI has made this recommendation as a longer dosing interval may increase how effective the vaccine is, as well as a potentially increasing the duration of protection. An 8-week interval is recommended by other countries such as Canada.

There is also a population-based study in Canada of people aged 12 years and older, which has shown that the risk of conditions like myocarditis (inflammation of the heart muscle) and pericarditis (inflammation of the outer lining of the heart) might be decreased with a longer interval between the first and second dose.

Which vaccine formulation should a person receive as their second dose if they turn 12 years after their first dose of vaccination?

ATAGI recommends that children who turn 12 years after their first dose should receive the Comirnaty (Pfizer) adolescent/adult formulation COVID-19 vaccine to complete their primary vaccine course.

What is the preferred anatomical site for IM vaccination of people aged 5 to <12 years of age?

The preferred anatomical site for intramuscular vaccination of children aged 5 to <12 years of age is the deltoid muscle.

How do I correctly identify the deltoid muscle in a child?

Locate the shoulder tip (acromion) and the muscle insertion at the middle of the humerus (deltoid tuberosity). Draw an imaginary line inverted triangle below the shoulder tip, using the identified anatomical markers. The deltoid site for injection is halfway between the acromion and the deltoid tuberosity, in the middle of the muscle. More information is available on the Australian Government Immunisation Handbook website.

How do I position a child for a vaccination?

The preferred position will be dependent on a number of factors including the child's age and comfort with vaccination.

Straddle position – sit facing the carer, with child straddling both of the carer's legs. The child's arms should be folded in front, and the carer should hug the child's body to their chest. More information is available on the Australian Government Immunisation Handbook website.

Solo sitting position for deltoid injections:

  • Sit in a straight-backed chair
  • Rest their feet on the floor
  • Relax their forearms and hands on the upper thighs
  • Keep their arms flexed at the elbow to encourage the deltoid muscle to relax

What are the side effects of Comirnaty Vaccine?

Common side effects after Comirnaty (Pfizer) vaccine include:

  • pain or swelling at the injection site
  • tiredness
  • headache
  • muscle pain
  • fever and chills
  • joint pain
  • fever.

Less common and uncommon side effects after Comirnaty (Pfizer) vaccine include:

  • redness at the injection site
  • nausea
  • enlarged lymph nodes
  • feeling unwell
  • arm pain
  • insomnia
  • decreased appetite
  • night sweats
  • physical weakness and/or lack of energy

Rare side effects that have been reported after Comirnaty (Pfizer) vaccine are:

  • severe allergic reaction (anaphylaxis)
  • inflammation of the heart muscle and/or the lining outside of the heart, called myocarditis and/or pericarditis
  • temporary one-sided facial drooping.

A patient factsheet is available and can be downloaded.

What should I do if a child refuses a vaccination that a parent or guardian has given consent for?

If a child or adolescent refuses a vaccination that a parent or guardian has given consent for, you should respect the child's or adolescent's wishes, and inform the parent or guardian. More information is available on the Australian Government Immunisation Handbook website.

How effective is Comirnaty (Pfizer) vaccine for children aged 5 to <12 years of age and how long will the protection from the vaccine last?

In phase 2/3 clinical trials, Comirnaty (Pfizer) demonstrated a strong antibody response in children aged 5 to 11 years of age when using a two-dose schedule, given 3 weeks apart. The antibody response in participants given the 5 to <12 years of age (lower) dose, were comparable to those recorded in a study of 16 to 25 year olds.

More information on how effective the vaccine is in a real-world setting and the duration of protection for children aged 5 to 11 years will be available over the coming months.

What are the contraindications to receiving the Comirnaty (Pfizer) 5 to <12 years of age formulation vaccine?

Contraindications:

  • anaphylaxis after a previous dose of the same vaccine
  • anaphylaxis to any component of the vaccine, including anaphylaxis to tozinameran, polyethylene glycol (PEG), distearoylphosphatidylcholine (DSPC) and trometamol.   
  • other serious adverse events attributed to the first dose of a COVID-19 vaccine.

Precautions:

People with the conditions below should be referred to a medical practitioner for assessment of suitability to be vaccinated.

  • an allergic reaction to a previous dose or ingredient of Comirnaty
  • anaphylaxis to other vaccines or to other medicines where there are common ingredients with the COVID-19 vaccine
  • history of syncopal (fainting) episodes following any needle injection
  • a known mast cell activation disorder
  • bleeding disorder
  • immunocompromising conditions or medications
  • history of confirmed COVID-19 infection
  • current illness
  • myocarditis or pericarditis.

Parents or guardians with any concerns regarding vaccination should be referred to a medical practitioner for additional advice.

What is myocarditis and pericarditis and does the Comirnaty (Pfizer) vaccine cause these conditions?

Myocarditis is inflammation of the heart muscle. Pericarditis is inflammation of the outer lining of the heart. Myopericarditis is where these two conditions occur together. There are many conditions that can cause myocarditis and pericarditis, and these include autoimmune conditions, viral and bacterial infection, certain cancers and certain medications. People who get COVID-19 can develop myocarditis and pericarditis. 

Myocarditis and pericarditis have been seen in people who have had mRNA COVID-19 vaccines (including the Pfizer vaccine) overseas. Cases have been reported more commonly in males aged <30 years, mostly after the second dose of vaccine and typically within the first few days of COVID-19 vaccination. The exact rate is not yet known but it is rare. Most cases have been mild and respond to simple measures such as pain relief. The WHO's Global Advisory Committee on Vaccine Safety and ATAGI continue to recommend that the benefits of mRNA COVID-19 vaccine strongly outweigh the risk of myocarditis or pericarditis.

Cases of myocarditis and pericarditis after vaccination have also been reported in Australia. The TGA is monitoring these cases. Both these conditions occur relatively commonly in the general population, and not all cases that are reported after vaccination will be caused by the vaccine (that is, some may occur coincidentally). 

Current as at: Tuesday 18 January 2022
Contact page owner: Health Protection NSW