Does herd immunity for measles exist?

The statement about measles vaccine coverage and herd immunity has several misleading or incorrect issues. Let’s break it down:

“The promise for herd immunity was a lie.”
Herd immunity is not a lie; it’s a well-established scientific principle. When enough people in a community are vaccinated against a disease, like measles, it can greatly reduce the likelihood of disease spreading in the community. This protects those who can’t be vaccinated, such as babies or people with certain medical conditions. The key is that a high enough percentage of the population needs to be vaccinated for herd immunity to work. For measles, this is usually around 95%.

“So now ‘vaccinated’ children are getting measles in epidemic numbers”
First, the vast majority of measles cases occur in unvaccinated individuals. While it’s true that no vaccine is 100% effective, the measles vaccine is very effective — about 97% effective after two doses. If community uptake rates dip below 95%, the risk for vaccinated and unvaccinated people increases. Let’s say 80% of children in a school of 200 students are vaccinated, and Unvaccinated Bobby brings measles back from his exotic vacation to the UK. We can be relatively certain that almost all of the 40 unvaccinated students will come down with measles. But, because the vaccine is only 97% effective, 5 vaccinated students could also become sick as the virus circulates through the student body. This isn’t an epidemic of the vaccinated. It’s math.

“Natural immunity has been decimated.”
This statement suggests that allowing a disease to run rampant through a community to create “natural immunity” is preferable to vaccinating them.  Before the measles vaccine, nearly everyone in the population got measles at some point in their life, although usually as children. Measles is so contagious that if 100 susceptible people were in a room with an active case, 90 of them would get measles. Today, very few people ever get measles because most people are vaccinated.

Relying on natural immunity means requiring virtually every child to get sick and 400-500 of them die every year.

Measles vaccination is a safe and effective way to prevent disease and protect public health. Herd immunity is critical to this protection, but it requires high vaccination rates to be effective. Vaccinated individuals are far less likely to contract measles than unvaccinated individuals, and the concept of natural immunity, while scientifically valid, comes with risks that can be avoided through vaccination.