Background

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

Primary schedule for children ≥ 12 to 17 years of age

  • Comirnaty (Pfizer) 30µ dose (0.3ml) - purple cap

    Dose 30µ dose
    Primary schedule 2 doses administered 8 weeks apart (can be reduced to 3 weeks in certain circumstances)
    Primary schedule for severely immunocompromised 3 doses, with the 3rd dose to be administered 2 months after the second dose

    NB: Comirnaty (Pfizer) 30µ is not registered for use in individuals ≤ 11 years (refer to dosing information for 5-11 year olds).

  • Spikevax (Moderna) 100µ dose (0.5ml) - red cap

    Dose 100µ dose
    Primary schedule 2 doses administered 8 weeks apart (can be reduced to 4 weeks in certain circumstances)
    Primary schedule for severely immunocompromised 3 doses, with the 3rd administered 2 months after the second

    NB: Spikevax (Moderna) 100µ is not registered for use in individuals ≤ 11 years (refer to dosing information for younger age groups outlined below).

  • Nuvaxovid (Novavax) 0.5ml

    Dose 100µ dose
    Primary schedule 2 doses administered 8 weeks apart
    Primary schedule for severely immunocompromised 3 doses, with the 3rd administered 2 months after the second

    NB: Nuvaxovid (Novavax) is not registered for use in individuals ≤ 11 years

Primary schedule for children 5 to ≤ 11 years of age

  • 5-11 years- Comirnaty (Pfizer) 10µ dose (0.2ml) - orange cap

    Dose 10µ dose
    Primary schedule 2 doses 8 weeks apart (can be reduced to 3 weeks in certain circumstances)
    Primary schedule for severely immunocompromised 3 doses, with the 3rd administered 2 months after the second

    NB: Comirnaty (Pfizer) 10µ is only recommended for use in individuals aged 5-11 years. It is not registered for use in anyone under the age of 5 or ≥ 12 years (refer to correct dosing information for ≥ 12 years as seen above).

  • 6- 11 years- Spikevax (Moderna) 50µ dose (0.25ml) - dark blue cap, purple vial label border

    Dose 50µ
    Primary schedule 2 doses administered 8 weeks apart (can be reduced to 4 weeks in certain circumstances)
    Primary schedule for severely immunocompromised 3 doses, with the 3rd administered 2 months after the second

    NB: Spikevax (Moderna) 50µ is only recommended for use as a primary course in individuals aged 6-11 years. It is not registered for use as a primary course in anyone under the age of 6 or ≥ 12 years (refer to correct dosing information for ≥ 12 years as seen above, and ≤5 years below).

Primary schedule for children 6 months to ≤ 5 years of age*

*Vaccination is currently only recommended in this age group for children with severe immunocompromise, disability or a complex medical condition that places them at a higher risk of severe COVID-19 disease. Children aged 6 months-≤ 5 years who do not fit these criteria are not recommended to be vaccinated at this time.

  • 6 months - ≤ 5 years- Spikevax (Moderna) 25µ dose (0.25ml) - dark blue cap, magenta vial border label

    Dose 25µ
    Primary schedule 2 doses administered 8 weeks apart (can be reduced to 4 weeks in certain circumstances)¥
    Primary schedule for severely immunocompromised 3 doses, with the 3rd administered 2 months after the second¥

    NB: Spikevax (Moderna) 25µ is only recommended for use in individuals aged 6 months – ≤ 5 years.

    ¥ COVID-19 vaccines may be co-administered with other vaccines however, it is preferable that there is an interval of 7-14 days between administering COVID-19 vaccines and other vaccines to children in this age group. This recommendation aims to minimise adverse events such as fever, which can occur in the 3 days following inactivated vaccines, and 7-10 days post vaccination with the live-attenuated MMR vaccine. The use of prophylactic paracetamol prior to vaccination is not routinely recommended but may be administered as required after vaccination.

Booster recommendations

3 months following a primary schedule of COVID-19 vaccination, an initial booster dose of Comirnaty (Pfizer) should be administered to all adolescents aged ≥ 16 years and a select group of 12-15 year olds. A further “winter” booster dose is also recommended for some individuals who have increased risk of severe disease.

Whilst Nuvaxovid (Novavax) is not registered for use as a booster dose, ATAGI recommends that it may be used for this purpose in individuals ≥ 12 years of age when no other vaccine brand is suitable (eg. allergy).

Spikevax (Moderna) is not currently recommended for use as a booster dose in any individuals ≤ 18 years. Booster doses are not currently recommended for anyone < 12 years.

Vaccine efficacy

Comirnaty (Pfizer)

12-15 years

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 Comirnaty. 18 cases of COVID-19 infection observed in the placebo group (n=1,129) versus zero cases in the vaccinated group (n=1,131).

5-11 years

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 Paediatric Comirnaty, 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)

12-15 years

3732 adolescents (12-15 years) participated in a phase 3 trial in the US investigating the safety and efficacy of Spikevax (Moderna) (100µ dose). 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.

6-11 years

Up to 4000 children (6-11 years) were recruited to the KidCOVE clinical trial across Canada and the United States. The immunogenicity, safety and efficacy of 2 doses of 50µ of Spikevax (Moderna) was assessed. Immunogenicity was comparable to that seen in individuals aged 18-25, with a good protection seen against COVID-19 disease.

6 months-5 years

2024 children aged 6 to 23 months and 3452 children aged 2-5 years participated in the phase 2-3 P205 clinical trial. Following administration of a two-dose primary course of 25µ of Moderna’s COVID-19 vaccine, the immune response of the infants and children was comparable to that seen in adults aged 18-25 years in earlier trials.

Results (>14 days after dose 2) demonstrated that in those without history of prior COVID-19 infection, vaccination was 50.6% effective in preventing disease in participants aged 6-23 months of age, and 36.8% in those aged 2-5 years. In those with a history of previous COVID-19 infection, vaccine efficacy against symptomatic COVID-19 disease was 52.1% for the 6-23 month group, and 34.5% in the 2-5 years group. There were no cases of severe COVID-19 disease reported in the study.

All of the cases of COVID-19 in this clinical trial were found to be the Omicron variant, likely the BA.1 strain, and not the currently circulating BA.4 and BA.4 variants which have demonstrated a higher degree of immune escape, meaning there is expected to be less protection against the BA.4 and BA.5 strains.

Nuvaxovid (Novavax)

12-17 years

2,247 adolescents aged 12-17 years participated in the paediatric expansion of the PREVENT-19 trial in the US. Results demonstrated 80% efficacy overall during a time where the delta strain was the predominant circulating strain of COVID-19. Following vaccination, immune responses were two-to-three-fold higher in adolescent vaccine recipients compared with adult vaccinees.

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, lymphadenopathy 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 and that Australian children aged 5-15 years report fewer side effects in the days following mRNA COVID-19 vaccination than those reported in clinical trials and published safety data.

Clinical trials involving children aged 6 months-5 years receiving Spikevax (Moderna), showed that fevers occurred more commonly in this age group following vaccination compared with rates of fevers experienced by other age groups. Rates of fever were highest in children receiving vaccination who had a history of prior COVID-19 infection.

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.

Resources 

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: Rachael McGuire (MVEC Education Nurse Coordinator) and Francesca Machingaifa (MVEC Education Nurse Coordinator)

Date: September 2, 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.