In the mid-20th century, several successful vaccines against polio were developed, eventually leading to an international initiative in 1988 to eradicate the poliovirus from the planet. After the success of smallpox eradication in 1980, the optimism of the initiative’s advocates and supporters seemed well placed. But some viruses are more unruly than others.
Is poliovirus eradication an achievable and worthwhile goal or a misapplication of public health efforts? Thomas Abraham poses this question in Polio: The Odyssey of Eradication, as he explores the complex and conflicting paths through the quest to see the end of polio. It’s a tale of personalities as well as biology, of evolution and ecosystems.
Discovery of polio’s key vaccines was first stalled by scientific missteps and later driven by scientists in competition. Many people dedicated their lives to the vaccination programs in hope of eradicating this disease, and others lost theirs to violent resistance against those same campaigns. Evolution and natural selection drove resurgence of new poliovirus strains in regions thought to be cleared. Poverty and remote geography enabled pockets of viral persistence. And the mismatch between where the motivation came from and where the action needed to happen weakened the end game.
Abraham comes to this topic as an outsider of sorts. Not an epidemiologist or medical historian, rather he is a professor who teaches health and science journalism. He extracts knowledge gained from analysis of documents of the World Health Organization and interviews with scientists. And he shares with the reader his own observations from remote parts of the world where poverty meets viral persistence.
The book contains good technical, but generally accessible, background on how the poliovirus works for its own interests at human expense. The biochemistry behind the vaccine discoveries and the molecular evolution that generated new strains are well explained. Abraham gets into more complex territory, though, when he delves into the motivations driving the eradication campaign and the campaign’s social impacts.
The poliovirus spreads in environments where poor sanitation contaminates water supplies. Children who encounter the virus early in life tend to be less affected, whereas children who are protected from early virus exposure by good water and sanitation systems may be left susceptible to more severe disease when they encounter the virus later on. Thus, better water and sanitation systems may have paradoxically increased the risk of severe disease, offering a potential explanation for why the U.S. polio epidemic seemed to hit children in well-off suburban neighborhoods particularly hard. But regardless of what drove the disease’s spread, the result was a hue and cry to stop the polio outbreaks from countries that had the scientific expertise and money to go after the problem.
Because of the efforts that ensued, large portions of the world are now free from the constant threat of polio. Not since 1979 has a case of polio originated in the United States, which is stunning progress given that some 58,000 cases of polio originated in the United States in 1952.
The 1988 initiative to completely eradicate polio worldwide, however, has failed to replicate this success. Abraham discusses the challenges to an eradication campaign in which motivation and application are not always pulling in tandem.
With polio cleared from wealthier nations, most of the action now occurs in developing areas, where public health systems must deal with a variety of pressing challenges, of which polio is only one. The virus persists in impoverished regions, where inadequate water and sanitation systems facilitate its spread. Weak health care systems struggle to sustain even minimal programs against scourges of childhood, ranging from measles to malnutrition.
The vaccines do work. But controlling the poliovirus has proven to be more difficult than expected. Abraham challenges us to apply lessons learned from the polio eradication campaign to inform future global public health endeavors. His book gives plenty for scholars to debate, particularly with regard to whether the passionate perseverance toward eradication defined by yesterday’s technology has outlived its usefulness. Then again, with fewer than 200 cases of poliovirus reported in 2017 (1), perhaps it would be better to persist.
World Health Organization; http://polioeradication.org/polio-today/polio-now.
About the author
The reviewer is on staff at Science.
The reviewer is on staff at Science.