When Health Canada approved the Pfizer-Biontech COVID-19 vaccine for children aged 12 and older, there were questions regarding its safety.

However, parents and their school-aged children — including those aged 11 turning 12 in 2021 — can be rest assured that Health Canada rigorously reviews the safety and effectiveness of vaccines to ensure that the benefits of vaccination far outweighs the small risk of side effects and adverse events.

Even more encouraging are the following numbers:


There were 40,000 participants aged 16 and older who were part of the Pfizer-Biontech clinical trial


There are 2,260 adolescents aged 12 to 15 in the ongoing C4591001 study

0 %

Close to 80% of everyone over 12 years old has received at least 1 dose of the COVID-19 vaccine as of July 2021

Side effects

School aged kids can expect the usual “reactogenic” side effects which are typical of a vaccine when building the important immune response. These are short lived, predictable, and typically only cause “mild discomfort” — including:

  • Sore arm
  • Headache
  • Chills and fever

With the extremely large number of people around the world receiving COVID-19 vaccines including school-aged kids, even the rarest of side effects can be detected through the required safety monitoring networks.

While not always directly caused by the vaccine, being aware of these potentially rare side effects can ensure it is managed quickly without any harm.

Heart inflammation

One signal that has emerged is pericarditis or myocarditis, which is also known as “inflammation of the heart”. While this may sound scary, it responds very well to treatment and rest, and a full recovery is expected. This condition also happens to those who have not received the vaccine, but rather infections (such as COVID-19) — posing a much higher risk of heart inflammation than vaccination.

Currently still being investigated, this is only an association between vaccination and this condition.

Risks perspective

More than 99.999% of those who have received vaccination will not be face heart inflammation.

  • It is more common in males under 30 years old after the second dose
  • Treatment is available
  • Rest and treatment will result in a full recovery

For multisystem inflammatory syndrome (which attacks the heart, lungs, kidneys, brain, and stomach organs), the risk of getting it from a COVID-19 infection is 10 times higher than from vaccination.