When a certain portion of a community (usually between 85-96%) is vaccinated against a contagious disease, it provides protection to the entire community. This theory is known as herd immunity.
With this effect, there is little opportunity for an outbreak. This can even lead to the eradication of diseases and help those who are not eligible for certain vaccines like new born babies, pregnant women, or immune-compromised individuals or those going through chemotherapy.
It’s important to get vaccinated, but for those who don’t want to get vaccinated, a very talented Reddit user, theotheredmund, has created this animation that shows how a contagious disease spread through different populations with varying percentages of its people vaccinated.
To demonstrate the concept of herd immunity, the creator leveraged the data based on research from a study published in Epidemiologic Reviews in 1993.
Theotheredmund explained, “You can see in the image, 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.”