I had a similar thought to this (and my kid is the same age as yours) but apparently immune response isn't based on weight - see e.g. https://www.nytimes.com/20

I had a similar thought to this (and my kid is the same age as yours) but apparently immune response isn't based on weight - see e.g. https://www.nytimes.com/2021/10/26/well/live/child-vaccine-dose-weight-age.html https://www.nytimes.com/2021/10/26/well/live/child-vaccine-d... . It's not like giving them Tylenol. That being said, after hearing about 10- and 11-year-olds pretending to be 12 so that they could get vaccinated I did have a moment where I wondered if she could pass for 5.