Herd immunity

In my epidemiology class last year we learned about herd immunity.

Herd immunity may be defined as the resistance of a group of people to an attack by a disease to which a large proportion of the members of the group are immune. If a large percentage of the population is immune, the entire population is likely to be protected, not just those who are immune…It happens because disease spreads from one person to another in any community. Once a certain proportion of people in the community are immune, the likelihood is small that an infected person will encounter a susceptible person to whom he can transmit the infection; more of his encounters will be with people who are immune.

This blog post by Aaron Carroll highlights what happens when the “herd” stops getting vaccinated. The map below came from the Council on Foreign Relations, and highlights vaccine preventable outbreaks.

A few things to note:
•All of that red, which seems to dominate? It’s measles. It’s even peeking through in the United States, and it’s smothering the United Kingdom.
•If you get rid of the measles, you can start to see mumps. Again, crushing the UK and popping up in the US.
•Both measles and mumps are part of the MMR vaccine.
•Almost all the whooping cough is in the United States.

Vaccinate your kids. Please.

All these outbreaks are preventable, with a vaccine. These infections can be life altering for your children. They are the ones that will suffer based on your decision not to vaccinate them. Don’t look for that one study that shows a link to a vaccine and XX, and ignore the countless others that say the vaccine is safe. Remember, we can always torture the statistics to make them give us the answer we want to hear. But in the end, who really suffers.


2 thoughts on “Herd immunity

  1. Very true statements regarding research, statistics and bias, however these truths apply across party lines. To single out liberals as guilty if distorting facts and confusing association with causation is to yourself expose your own bias.

    • I completely agree Billy. All of us have a bias, the right, middle, and left. Sometimes it is easier to accuse the other side of being biased, than to know and understand our own biases.


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