Comirnaty 5 to 11 year olds Clinical Trial and Real World Data

EMA and NIAC Recommendations

The European Medicines Agency (EMA) recommended extending the indication for the COVID19 vaccine Comirnaty to include use in children aged 5 to 11 years of age on the 25th of November 2021. The dose recommended for this age group is 10 micrograms.

Read more here:


The National Immunisation Advisory Committee (NIAC) provided recommendations on COVID19 vaccination in children aged 5-11 years on the 7th of December 2021. NIAC strongly recommended COVID19 vaccination for those aged 5-11 with underlying conditions, those living with a younger child with complex medical needs or a person who is immunocompromised.

NIAC also recommended that COVID-19 vaccination should be offered to all other children aged 5 to 11 years because of the favourable benefit risk profile of the vaccine, to protect them from severe disease, the consequences that can follow infection e.g., multisystem inflammatory syndrome in children (MIS- C), long COVID, psychosocial and developmental impacts.

COVID-19 infection in those aged 5 to 11 years is usually asymptomatic or mild. Risk of hospitalisation is higher in children with underlying conditions. However, previously healthy children can also develop severe COVID-19. In Ireland, 7 in 10 children admitted to hospital who had COVID-19 in this age group had no underlying health conditions.

Read more here:


Clinical Trial Data

EMA and NIAC recommendations were based on a clinical trial of the Comirnaty vaccine involving 2268 children aged 5 to 11 years (1518 children received the Comirnaty vaccine and 750 children received a placebo).

Results of this clinical trial showed the Comirnaty vaccine at a dose of 10 micrograms is 90% effective at preventing COVID19 infection in children aged 5-11 years.

No safety concerns were identified in this initial clinical trial. The study size however did not allow for detection of rare or very rare adverse events.

There is an additional safety group trial including 2379 children (1519 received Comirnaty vaccine and 788 received a placebo) who will be followed up for 2 years.

Side effects were usually mild to moderate, and similar to those seen in  those ages 12 and older.  They include pain at the injection site, tiredness, headache, redness and swelling at the site of injection, muscle pain and chills.

Read more here:


Myocarditis and Pericarditis

The EMA has listed Pericarditis and myocarditis as a very rare side effect of the Comirnaty vaccine (up to 1 in 10,000 vaccinated people may be affected). The risk is highest in younger males and after the second dose. Available data suggest the course of myocarditis following vaccination is similar to the typical course of these conditions. Long term follow up of these cases is ongoing.

Read more here:


In the United States over 8 million doses of the vaccine have been given to children aged 5-11. Serious adverse events were rare. There were only 11 confirmed reports of myocarditis.

Furthermore in the same age group (using active safety surveillance system ) after 333,000 vaccine doses there were no confirmed reports of myocarditis observed within 42 days of vaccination.

Read more here:


Two large European studies have estimated the myocarditis risk after a second dose of mRNA vaccines:

  • one additional case for every 38,000 men aged 12 to 29 (within 7 days).
  • one additional case for every 17,500 men aged 16 to 24 (within 28 days).

Read more here:

No cases of myocarditis or pericarditis were noted in the clinical trials of 5-11 year olds, however the study size was too small to detect this rare event.


COVID-19 Vaccination Protects against Multisystem Inflammatory Syndrome (MIS-C) in Children Aged 12-18 years

Multisystem Inflammatory Syndrome in Children

  • Multisystem Inflammatory Syndrome in Children (MIS-C) is a rare but serious inflammatory condition linked to COVID19 infection in children. MIS-C is also known as paediatric inflammatory multisystem syndrome (PIMS). MIS-C can affect the heart, lung, kidneys, brain, skin, eyes or gastrointestinal organs.
  • Most children have gotten better with hospital care but some children with MIS-C require life support. We are still learning about this condition. However, many children that have had MIS-C appear to have had SARS-CoV-2. Children usually develop MIS-C two to six weeks after an asymptomatic or mild Covid19 infection.
  • Early studies appear to suggest that vaccination may be protective against complications of COVID-19 such as MIS-C in adolescents. 

CDC Study

  • A study by the CDC in the United States looked at 283 hospitalised patients aged 12-18 years between July and December of 2021.
  • The study found that 2 doses of the Pfizer COVID19 vaccine was 91% effective at protecting children aged 12-18 years against MIS-C. All MIS-C patients that required life support were unvaccinated.

Read More Here: Effectiveness of BNT162b2 (Pfizer-BioNTech) mRNA Vaccination Against Multisystem Inflammatory Syndrome in Children Among Persons Aged 12–18 Years — United States, July–December 2021 | MMWR (

Study in France

  • A study in France looked at vaccination status of patients aged 12-18 years diagnosed with MIS-C .
  • Of the 33 children aged 12-18 years hospitalised in France with MIS-C between September 1st to October 31st 2021, none were fully vaccinated. 7 of the patients had received 1 dose of a vaccine and the remaining 26 had not received any dose of COVID19 vaccine.  

Read More Here:

Real World Data

The Comirnaty vaccine has been approved for  younger children in the United States, Canada, Israel, Australia and New Zealand.

In the United States more than 7.5 million US children ages 5-11 have received at least one dose of COVID-19 vaccine.

Read more here:

This page was updated on 7 February 2022