Sarah Lichtner

For my generation, polio, measles, and smallpox are diseases we learned about in history books or heard stories about from older generations. My mom, for example, remembers being quarantined in her room when she had measles at five, lining up at the local firehouse for her polio vaccine, which at the time was administered on a sugar cube, and developing the scar left by the smallpox vaccine. I, on the other hand, have never had to give much thought to these diseases. Smallpox was eradicated before I was born, and I was vaccinated for polio and measles before I was even old enough to remember. Yet today, all three of these diseases are at the forefront of global health conversations.

Polio – To date, the World Health Organization (WHO) estimates that the polio vaccine has prevented the paralysis of more than 10 million people and has saved the lives of more than 1.5 million children. Worldwide, polio cases have decreased by 99% in just 2.5 decades, dropping from 350,000 cases to just 406. Unfortunately, the decline of children being vaccinated has led to the recent reemergence of polio in areas of Central Asia, the Middle East, and Central Africa, some of which were previously declared polio-free. So far this year there have already been nearly three times as many new cases compared with this time last year. Efforts to eradicate the disease are in jeopardy from the decrease in vaccinations.

Measles – The reemergence of vaccine-preventable diseases isn’t isolated to countries overseas; the United States is currently experiencing its largest measles outbreak since 1996. In 2000, measles had been almost completely eradicated in the U.S., with only 60 cases compared with the 500,000 annual cases before the vaccine. So far this year, there have been 154 measles cases in 14 states, with the greatest numbers in California and New York. While none of these U.S. cases have been deadly, the disease still takes its toll worldwide at the rate of 14 deaths every hour.

Smallpox – The smallpox vaccine is the vaccine success story. It achieved what all other vaccines strive to achieve: complete eradication of the disease it was designed to prevent. Smallpox, which was responsible for more than 300 million deaths in the 20th century, was eradicated in 1979. All that remains of the disease are small frozen test tubes of live samples at the Centers for Disease Control and Prevention (CDC) in Atlanta and at laboratories in Russia. This month, WHO will decide whether these samples should be destroyed now that the disease has been eradicated. Some scientists argue that the samples can help resolve unanswered questions and develop even better vaccines, diagnostics, and drugs for treating smallpox and other similar viruses. There is also a fear that it could resurface because scientists don’t know how long the virus can survive in dead tissue. Other scientists argue that smallpox research could continue without the live samples by testing on similar viruses or by studying the fragments of the smallpox genome that have been sequenced. Just a few more weeks remain before WHO decides the fate of this 8,000- to 10,000-year-old disease.

WHO estimates that vaccines currently prevent 2 million to 3 million deaths each year, and the CDC now lists 28 vaccine-preventable diseases. With more effective deployment of vaccines and the continuous development of new vaccines, even more cases of infection and disease-related deaths could be prevented. I’m sure scientists would love to be deciding the fate of more diseases that once killed millions but that are now confined to laboratories.