Fatima Tokhmafshan

Fatima Tokhmafshan

Member of CoVaRR-Net (Community and Patient Engagement and Outreach Director)

Why do all children from 5 to 11, despite their differing ages and weights, receive the same vaccine dose?

Vaccines are very different than medications. Whereas medications are measured by a person’s weight, vaccines doses are based on the smallest amount of the compound that can generate a strong immune response with the least amount of expected side effects.

When medication is taken, it gets metabolized by certain organs and is then eliminated from the body. When a vaccine enters the body, it targets the immune system as a whole. Tokhmafshan uses the analogy of the vaccine being a sheriff, which deputizes antibodies to catch the virus if it ever shows itself.

So why is an 11-year-old getting 10 mg whereas those 12 years old and up are getting 30 mg?. In general, children’s immune systems are more robust, and require very little to trigger an immune response. The age cut-off is based on previous knowledge and data.

You don’t need to adjust the amount of vaccine for height or weight, since a child’s immune system recognizes pathogens from small amounts of exposure. Additionally, immune systems need to be reminded what the pathogen looks like after the initial dose. That’s where a second dose comes in.

Download a document showing the booster dose recommendations for provinces and territories in Canada as of November 11, 2021.

To arrange an interview with Dr. Tokhmafshan, please contact:
Philip Fine