Fun Science FRIEDay – Immune System Amnesia

Ah the measles, a childhood illness that most of my generation has never experienced; due in large part to the success of measles vaccination. A lot of people think the measles isn’t that big of a deal, its just some combination of a rash and fever that goes away in due time. While this is true in most people, in about 1 in 1,000 cases the infection becomes systemic and moves to the brain resulting in death, in what is known as  measles encephalitis.  The measles vaccination resolved this issue but also had an unexpected secondary effect.

16th-century Aztec drawing of someone with measles (Photo credit: Unknown – (2009) Viruses, Plagues, and History: Past, Present and Future, Oxford University Press, USA, p. 144)

When the measles vaccine was first introduced in America in the 1960s, scientists were perplexed why childhood deaths from all infectious diseases plummeted along w/ the measles; even deaths from diseases like pneumonia and diarrhea were cut in half.  An obvious assumption was the drop in childhood deaths was just a result of our advances in modern medicine. While there is undoubtedly truth in the assertion that modern medicine was advancing rapidly in the mid-20th century, whenever the measles vaccine was introduced to Europe a few years later, and even now as its being introduced to third world countries, the same phenomena has been observed. Places that have the measles vaccine see a steep decline in deaths from all other childhood diseases. So whats going on?

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