Reports that a man in his 20s in New York state contracted polio and detection of poliovirus in wastewater samples in two New York counties leave many wondering how this could happen in a country that has eliminated the disease. This is a good lesson in how easily infectious diseases spread and underscores the importance of protecting people around the world with vaccines.
As officials gather details of this particular case, some important facts are known. This individual was not vaccinated against polio. Those who have been vaccinated — the vast majority of Americans — are considered to be at very low risk for polio-related paralysis. This new case in New York is a stark reminder that until all forms of polio are wiped out, and the disease is eradicated, people in every country remain at risk.
Polio is just one example of infectious diseases traveling quickly around the world. One of us (P.P.) is an immunologist who was on the frontlines in New York City when Covid-19 first appeared there, just weeks after the disease emerged in Wuhan, China. The other (M.R.) has traveled to vaccine clinics around the globe, including in the Democratic Republic of Congo this summer, a country that is still recovering from a fast-spreading measles outbreak a few years ago that claimed thousands of lives.
A form of poliovirus anywhere is a threat to children everywhere, so surveillance and vaccination in the coming weeks will be critical.
Polio once terrified American parents, and with good reason. In the late 1940s, polio disabled more than 35,000 people, many of them children, each year in the U.S. Then a vaccine was created. Following its introduction in 1955, the number of polio cases fell dramatically, dropping to less than 100 annually in the 1960s and fewer than 10 cases per year in the 1970s. The last case originating in the U.S. was in 1979. Vaccines work.
Polio is not curable, but it is preventable with vaccines. Wild polioviruses cannot survive long outside the human body, and if they cannot find an unvaccinated person to infect, they die. That makes it possible to eliminate — or even eradicate — polio through vaccination, much as was done with smallpox.
The world came together on a mission to eradicate polio in 1988, and established the Global Polio Eradication Initiative. This gargantuan effort included setting ambitious goals and working closely with all levels of health care delivery, from ministries of health down to local volunteer community health workers.
We witnessed the power of polio vaccination efforts when we traveled to a rural health clinic in Zambia. Health care workers patiently spent hours preparing and administering vaccines to babies who had waited in long lines, held by their mothers. We spoke to these mothers and learned that they had come to the clinic, many walking from far away, because they had seen children contract polio and become paralyzed. The global movement combined with very local efforts to reach all children have decreased by 99% the number of polio cases caused by the wild poliovirus since 1988. (The U.S. and many other countries use shots made with an inactivated version of the virus which cannot cause polio. Some countries, however, give an oral vaccine containing weakened live virus because it is cheaper and easier to administer, and in rare instances, that weakened virus can mutate into a non-wild form that can cause polio in unvaccinated immunocompromised individuals.) Polio caused by the wild poliovirus is endemic in only two countries, Afghanistan and Pakistan, though Malawi and Mozambique have reported cases in the past six months.
The world is currently at a unique tipping point, with an opportunity to stop the transmission of poliovirus for good — or allow it to continue spreading.
Millions of children around the globe have not been vaccinated against polio and so are vulnerable to this devastating disease. As the Covid-19 pandemic has shown, infectious diseases can easily traverse long distances, especially among unvaccinated people. It has also shown how unvaccinated people become launching pads for future variants. To prevent future polio outbreaks, we need to do all we can to eliminate the disease in all countries.
To seize the opportunity to stop polio for good, countries and donors need to commit to fully supporting and funding the Global Polio Eradication Initiative at the World Health Summit in Berlin in October.
Eradicating polio hinges on engagement at all levels of the polio eradication program, from individuals to communities to local and national governments to donors. If the strategies needed to reach and vaccinate children are fully implemented and funded, a world where no child lives in fear of polio can be achieved.
The U.S. has historically been one of the initiative’s most committed and generous partners and it’s essential the country continue to support this final stretch of the eradication effort. The consequences of failing to fully fund the polio eradication strategy would be dire. Without a strong commitment, hundreds of thousands of children will be at risk of paralysis from a vaccine-preventable disease.
Martha Rebour is the executive director of [email protected], a grassroots advocacy campaign of the United Nations Foundation that champions global childhood immunization. Purvi Parikh is an immunologist, co-investigator in several Covid-19 vaccine trials, and a [email protected] champion.