Polio: An Old Scourge in a Changing Environment
Source: NJ.com
As we approach the third year of the COVID-19 pandemic, infectious diseases — monkeypox, respiratory syncytial virus (RSV), and, shockingly, the near-eradicated poliovirus — continue to dominate our headlines. Polio, an extraordinarily infectious disease with a long history tracing back to ancient Egypt over three millennia ago, is spread by contact with feces, sneezes, or coughs – has been noted for its ability to cause paralysis.
While most polio cases lead to mild flu-like symptoms or no symptoms at all, approximately 1 in 200 individuals with poliovirus infection develop paralysis. However, vaccination provides a formidable defense. The vaccine is highly effective against paralytic polio, which has led to a 99 percent reduction in global polio incidence and protected an estimated 16 million people from paralytic polio. The vaccine has been so successful that polio has been targeted for total eradication by the World Health Organization and partners.
However, with the disruption of the COVID-19 pandemic and an increase in vaccine hesitancy, polio vaccination rates are historically low. Consequently, polio rates have troublingly increased. With the population less protected against polio, recent reports of a return of the disease in New York are a cause for concern.
In the setting of these lower vaccination rates, evidence of local polio transmission in New York was reported in July 2022 for the first time in over 40 years, after paralytic polio was discovered in Rockland County. The detection of poliovirus in wastewater supported further evidence of local transmission. This outbreak means that the United States is now one of just approximately 30 countries with local poliovirus transmission.
While we have not seen a proliferation of paralytic polio cases in New York, officials remain concerned about the continued detection of poliovirus in wastewater sampling. In using this strategy of wastewater surveillance, public health officials can detect transmission of viruses that cause mild diseases, such as non-paralytic polio or asymptomatic cases of COVID-19. Hence, while we may have lower vaccination rates, the ability to detect disease transmission has improved significantly in recent decades.
As the world endures the seemingly perpetual COVID-19 pandemic and contemplates the threats of emerging viruses such as monkeypox and old enemies such as poliovirus, the threat of the microbes that surround us feels increasingly pressing. Yet, while navigating the calamitous headlines to disastrous Breaking News segments, it is critical to consider the tools we now have at our disposal.
First and foremost, vaccinations save lives. In many cases, vaccination is a crucial tool at our disposal to avoid illness and the sequelae of infections. With a changing climate, transmission patterns of diseases such as polio will likely shift, testifying to the importance of population-level protection in the context of an uncertain environment. If we let our guard down against old scourges, such as polio, we are more vulnerable to new outbreaks.
Second, investment in modern infrastructure prevents disease. For diseases like polio, which primarily spreads through the fecal-oral route, sanitation improvements and public investment in infrastructure provide a significant boon to public health and help prevent exposure to dangerous pathogens.
Finally, our scientific capabilities to detect and identify pathogens with techniques such as wastewater surveillance protect us from difficult-to-detect viral transmission. These warnings arm us with information to guard ourselves against viral threats that lurk, sometimes quite literally, in the sewers. It is up to us to use this information to vaccinate, advocate, and protect those most vulnerable to these threats.
