Overall children more commonly experience mild symptoms of COVID-19 disease compared with adults, however infection, particularly in adolescents, still occurs at similar rates. Emerging variants of COVID-19 disease demonstrates a high transmissibility of infection across all age groups, including children.

There are certain medical conditions which may increase the risk of severe COVID-19 disease in children and these can include:

  • obesity
  • Trisomy 21
  • immunosuppressive conditions
  • malignancies
  • diabetes
  • respiratory conditions such as cystic fibrosis and severe asthma
  • heart disease
  • chronic liver diseases
  • neurological conditions
  • disability.

COVID-19 vaccination provides protection against severe COVID-19 disease and hospitalisation and is particularly important for those who have been identified at higher risk of severe disease.

Vaccines available

Two vaccines are provisionally registered in Australia for use in children.

Children ≥ 12 years of age:

Comirnaty (Pfizer) is a 2 dose course administered 3-6 weeks apart (3 doses are required for immunocompromised individuals with the 3rd dose to be administered 2-6 months after the second).

Spikevax (Moderna) is a 2 dose course administered 4-6 weeks apart (3 doses are required for immunocompromised individuals with the 3rd dose to be administered 2-6 months after the second).

Children aged 5-11 years:

Comirnaty (Pfizer) is a 2 dose course of 10 micrograms (compared with 30 micrograms administered to those ≥ 12 years) administered 8 weeks apart. This interval can be shortened to a minimum of 3 weeks in special circumstances.

NB: Clinical trials are currently underway internationally to assess the safety and efficacy of COVID-19 vaccination in children ≥ 6 months of age.

Vaccine efficacy

Comirnaty (Pfizer)

2,260 adolescents (aged 12 to 15 years) were enrolled in a phase 3 trial in the United States (US). A good safety profile and strong immune response was observed with 100% efficacy 7 days after dose 2 of the vaccine. 18 cases of COVID-19 infection observed in the placebo group (n=1,129) versus zero cases in the vaccinated group (n=1,131).

2,268 children (aged 5 to 11 years) participated in a phase 2-3 clinical trial. Participants in the vaccine group were administered a 2 dose course of 10 micrograms of Comirnaty (Pfizer), 21 days apart. A similar safety profile to that seen in the ≥ 12 year old age group was observed in this younger cohort. A robust immune response was reported with a vaccine efficacy of 90.7% more than 7 days after the second dose. 3 cases of COVID-19 disease were observed in the vaccine group (n=5,157) and 16 cases among the placebo group (n=751).

Spikevax (Moderna)

3732 adolescents (12-15 years) participated in a phase 3 trial in the US investigating the safety and efficacy of Spikevax (Moderna) in children. Results from this trial have demonstrated an efficacy against confirmed symptomatic COVID-19 disease of 93.3% (commencing 14 days after dose 2 of vaccine. 1 case in vaccine group, 7 cases in placebo group). There were no cases of severe COVID-19 or deaths in the study cohort.

Side effects of vaccination

Common side effects

Most side effects following COVID-19 vaccination are mild and can include pain at the injection site, fatigue, headache and fever. Surveillance of adverse events occurring in Australian adolescents has shown that these symptoms typically resolve within 3 days. AusVaxSafety data shows that adolescents have reported fewer side effects following vaccination with Comirnaty (Pfizer) than adults receiving the same vaccine.

Rare side effects

Myocarditis (inflammation of the heart muscle) and pericarditis (inflammation of the lining around the heart) are rare conditions that have been reported following administration of mRNA COVID-19 vaccines (Comirnaty and Spikevax). They are most commonly associated with viral infections (including COVID-19 disease) but can also be triggered by other factors such as medications and autoimmune conditions. In the setting of vaccination the peak risk group for myocarditis is young adult males aged between 16-24 years old following a second dose of mRNA vaccine. Pericarditis occurring after vaccination is more common in the 20-45 year old age group for both males and females.

Deciding to vaccinate

Consideration of the benefits and risks of COVID-19 vaccination in the child and adolescent group is a delicate balance. Factors to consider include:

  • efficacy and safety profile of vaccines specifically in these age groups
  • data on complications of COVID-19 disease in the child and adolescent group, including conditions such as Paediatric Multisystem Inflammatory Syndrome Temporally associated with SARS-CoV-2 (PIMS-TS), as well as long COVID-19 symptoms
  • children in specific subgroups, such as those with underlying medical conditions and Aboriginal or Torres Strait Islander Peoples may be at higher risk of severe outcomes
  • amount of circulating COVID-19 disease
  • other impacts on children and adolescents such as mental health harms and disruptions to socialisation and education.

What other strategies are there to reduce transmission of COVID-19 in the paediatric age group?

Non-vaccination strategies to reduce risk of transmission of paediatric COVID-19 disease are also important.

The “cocooning” impact of having adults (parents and teachers) in the household and classroom vaccinated is currently the best way to protect children, especially those who are currently ineligible for COVID-19 vaccination.

Consideration of multi-layered mitigation strategies within a school setting comprising of a combination of standard precautions, such as hand hygiene, along with other strategies such as masking, adequate ventilation and appropriate distancing are also important.


Authors: Davina Buntsma (MVEC Immunisation Fellow), Daryl Cheng (MVEC Medical Lead), Francesca Machingaifa (MVEC Education Nurse Coordinator) and Rachael McGuire (MVEC Education Nurse Coordinator)

Reviewed by: Daryl Cheng (MVEC Medical Lead), Rachael McGuire (MVEC Education Nurse Coordinator) and Francesca Machingaifa (MVEC Education Nurse Coordinator)

Date: January 20, 2022

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