Two weeks ago I wrote about the reemergence of polio in Syria and the Herculean task the World Health Organization faces to eradicate the disease – the vaccination over a million children in the Middle East, some of whom live in a war zone. (See that post for a review of the symptoms of polio and the history of polio eradication in the West.)

This week’s post is about another polio outbreak which was managed very differently. On July 3, 2011 a 16-month-old girl in Xinjiang Province, China became paralyzed. The polio outbreak that followed and the efforts of the public health authorities to track and extinguish the infection are published in an article in this week’s New England Journal of Medicine.

China had eliminated polio by 2000, though it has had small outbreaks of polio imported from other countries since then. The public health response in the summer and fall of 2011 involved a multifaceted attack, including mandatory reporting of all cases of acute paralysis, laboratory testing of patients and their close contacts, and a mass vaccination campaign for vulnerable populations.

Over the subsequent months 21 cases of polio were confirmed and 23 more were suspected but did not yield laboratory confirmation. Over 1,000 health workers were trained to respond to the outbreak and over 43 million doses of vaccine were administered over the following year. A massive media campaign including text messages informed the population of the vaccination program. The study authors estimate that the public health response cost approximately $26 million.

The last confirmed case of polio in the region was in October 2011. The outbreak was stopped within four months of the initial case. Genetic testing of the isolated virus suggested it had been imported from Pakistan, though no contact of the initial patient with a traveler from Pakistan was discovered.

The contrasts between the Syrian outbreak and that in China are stark. The contrast reminds us that a robust public health infrastructure is critical. But in the age of global travel even this well-organized and well-funded public health system was insufficient to keep the country free of polio. The authors of the article and an editorial in the same issue emphasize the point that until polio is eradicated globally even advanced countries will be at risk of outbreaks.

In the meantime, surveillance and vaccination efforts in the US must be recognized as the front line against an ever-present threat. Some parents who are suspicious of vaccines believe that vaccination against diseases like polio is no longer necessary because of the long history of polio eradication in the US. Because of the importance of herd immunity, these ideas were always wrong. As recent outbreaks teach us, these ideas are also very dangerous.

Learn more:

Polio-free countries still face threat, scientists say (Fox News)
Polio Outbreak Can Be Halted in Its Tracks (MedPage Today)
Identification and Control of a Poliomyelitis Outbreak in Xinjiang, China (NEJM article, free without subscription)
No Country Is Safe without Global Eradication of Poliomyelitis (NEJM editorial)
Polio Outbreak in Syria (my post two weeks ago)

Tangential Miscellany

Last week I wrote about new guidelines for cholesterol treatment. Unfortunately a risk calculator that physicians are supposed to use to calculate patient risk of stroke and heart attack seems to be malfunctioning. This New York Times article reports the problem with the calculator. So for now, the fourth group of patients for whom statins are to be prescribed is on hold. I know you join me in hoping that the calculator is fixed soon, perhaps with the help of any spare programmers from the site.