America may get Measles for Xmas

Measles is a highly contagious virus. How infectious is it? It has a reproduction number of 12 – 18, although recent studies show that this can be quite variable. So what does the reproduction number mean? That is the number of susceptible individuals someone with measles infects. In other words, if a child is sick with measles, they will, on average, infect 12 to 18 naive individuals with the virus. That is wildly higher than many other viruses. The seasonal influenza virus has a reproduction number of 1.2 to 1.4. Measles spreads like crazy. If a child enters a daycare and is contagious, they will spread the virus to anyone susceptible. Imagine a forest with lots of ground cover, and then someone spreading gasoline all over it. All you need is a match (one case of measles) and the whole forest goes up.

In the past, this wasn’t a big deal, because everyone, and I mean everyone, was vaccinated (almost everyone). Vaccination rates against measles were greater than 95%. This all began to change when Andrew Wakefield published a flawed paper claiming a link between autism and the MMR vaccine. I tear this paper apart in a section of my textbook Why Microbes Matter. This set back decades of vaccine public policy as a significant minority of parents began not to vaccinate their children.

Rates of vaccination for measles have now reached a critical milestone. To prevent the spread of measles, public vaccination rates need to be above 95%. They have now dipped below that critical threshold. Rates vary considerably across the United States, and this will dictate where the outbreaks occur. The CDC has an amazing tool that lets you track vaccination rates down to the state and, in some cases, the city level. Here is the most recent map from 2024. I expect that in the next few years we will have serious outbreaks of measles in places like South Carolina (85% coverage), Texas (85%), Oklahoma (89.2), and California (90.5). That match will come, and fires will burn all over the place. Sadly, children will die of a completely preventable disease. It’s easy to protect yourself and your children. Make sure you are up to date on your MMR vaccine!

Measles is not an illness to toy with. It can be quite severe. To learn more about measles and why you should get vaccinated, please read the wealth of information put out by the Centers for Disease Control and Prevention.