The latest figures: Between January 1 and August 29 of this year, nearly 600 confirmed measles cases were reported to the CDC's National Center for Immunization and Respiratory Diseases. The resurgence is the greatest the U.S. has seen since the disease was eliminated from the country in 2000.


Notably, it has not taken the U.S. eight months to reach this ugly milestone. By May, the country had already seen 288 cases of measles – the most in a five-month period since 1994, and more than had been reported for a given year in well over a decade. The cause for the resurgence is as unambiguous today as it was then. To quote Dr. Anne Schuchat, assistant surgeon general and director of the CDC's National Center for Immunization and Respiratory Diseases: "The current increase in measles cases is being driven by unvaccinated people."


The harmful effects of vaccine-refusal have not been limited to measles' comeback. California, the most populous state in the U.S., has become a case study in what happens when people decide against vaccinating their children. The L.A. Times reports California parents today are opting out of vaccinating their kids at twice the rate they did seven years ago. State health officials say insufficient vaccination has contributed not only to the the widespread reemergence of measles, but the ongoing whooping cough epidemic, and has left the state vulnerable to outbreaks of other serious diseases.

"We have schools in California where the percent of children who exercise the personal belief exemption is well above 50%," Dr. Gil Chavez, deputy director of the California Department of Public Health's Center for Infectious Diseases, told the LAT. "That's going to be a challenge for any disease that is vaccine preventable."

What kinds of diseases are vaccine-preventable? There are literally dozens. Some, like flu, are obvious; others – like cervical, anal, throat, and penile cancers – are, unfortunately, less-so. Many, like measles, are highly contagious. And the key to stopping all of them is timely immunization.


It bears mentioning that, despite anti-vaxxer rhetoric, a recent investigation led by Yale psychologist Dan Kahan found that vaccination rates and public acceptance of vaccination are actually very high, illustrating that anti-vaccination advocates account for a small, albeit very vocal, minority of the population. On one hand this is encouraging. On the other, it's unsettling to see the effect that a slight dip in vaccination rates can have in places like California, where the percentage of kindergartens in which at least 8% of students are not fully vaccinated has more than doubled in the last seven years. For diseases like measles and whooping cough, the threshold for herd immunity – the phenomena by which a high rate of vaccination in a community protects even those individuals who have not developed an immunity – is 92%.


Earlier this year, Keren Landsman noted at Aeon that "the great allies of infectious diseases are no longer poverty, nor dirt, but the global anti-vaccination movement." That movement may be small, but its harmful effects are already making themselves known in frightening ways.

Vaccination has been shown over and over again to be a safe, simple, and effective way to save lives. Educate yourself. Learn to discern fact from fiction (and fiction's oft-cited cousin, correlation).



[CDC]