Herd immunity is the idea that if enough people get immunized against a disease, they’ll create protection for even those who aren’t vaccinated. This is important to protect those who can’t get vaccinated, like immunocompromised children.
You can see in the image how low levels of vaccination lead to everyone getting infected. Medium levels slow down the progression of the illness, but they don’t offer robust protection to the unvaccinated. But once you read a high enough level of vaccination, the disease gets effectively road-blocked. It can’t spread fast enough because it encounters too many vaccinated individuals, and so the majority of the population (even the unvaccinated people) are protected.
Find out more here.
To be clear: herd immunity is not a good reason to not vaccinate your damn kids. Herd immunity works to protect those who cannot be vaccinated (by dint of being too young, too old, or otherwise immunocomprimised). Your damn kids are the wall between those very few who can’t be vaccinated and a potentially deadly disease. Not vaccinating kids that can be vaccinated means herd immunity fails. Look at that graphic for 75% vaccine penetration - it’s slower, but that disease still spreads through the entire damn community.
VACCINATE YOUR DAMN KIDS!
