Editor’s Note: Syra Madad, DHSc, MSc, MCP is an infectious disease epidemiologist, faculty at Boston University’s Center for Emerging Infectious Diseases Policy and Research, senior director of the system-wide special pathogens program at NYC Health + Hospitals and is currently responding to the monkeypox outbreak in NYC. She is also a fellow at the Belfer Center for Science and International Affairs. She tweets @syramadad. The views expressed in this commentary are her own. View more opinion at CNN.
New York City has detected poliovirus in sewage, according to state and local health officials, suggesting likely local circulation of the virus. This comes as no surprise since last month a case of paralytic polio was confirmed in a resident in Rockland County – just on the outskirts of the city. As the state health commissioner Dr. Mary T. Bassett said, “For every one case of paralytic polio identified, hundreds more may be undetected.”
This follows the virus being found in sewage in two neighboring New York City counties – Rockland and Orange County from samples collected in May, June and July. While no other cases of polio have been reported in the US so far, a senior official with the US Centers for Disease Control and Prevention said on Wednesday that this is “just the very, very tip of the iceberg,” suggesting that there “must be several hundred cases in the community circulating.”
This is a serious situation. Poliovirus – a disease eliminated in the US in 1979 is now being detected in three locations in the US. “Polio is entirely preventable and its reappearance should be a call to action for all of us,” said the New York CityHealth Commissioner Dr. Ashwin Vasan.
Polio is a vaccine preventable disease and these latest developments should be a warning to us all. Unfortunately, places like Rockland County have an incredibly low polio vaccination rate; 60.5% of two-year-olds are vaccinated compared with the statewide average of 79.1%.
The vaccine to fight the disease has indeed been one of the most celebrated shots in history. Church bells rang out across America and people flooded into the streets to celebrate with parents hugging their children in relief when the vaccine field trial results were announced in 1955 (this is akin to present-day pharmaceutical companies releasing news releases on their vaccine efficacy data).
The celebration was warranted; through vaccination, the US eliminated wild, or naturally occurring, poliovirus more than 40 years ago.
As a parent of three, I can’t image living through the daunting threat of polio potentially infecting my children. Before a polio vaccine was made available, some parents were hesitant to even let their child go outside for fear of them being exposed, especially in the summer months when polio seemed to peak.
If we take a trip down memory lane, the worst recorded polio epidemic in the US occurred in 1952 when 58,000 cases were reported. More than 21,000 people were left with mild to disabling paralysis (most victims were children) and over 3,000 people died. What was once a crippling disease was thwarted through mass vaccination.
Polio is a highly contagious virus that spreads through person-to-person contact (most commonly through contact with an infected person’s poop). While most people who get infected do not experience any symptoms, about 1 in 4 people develop flu-like symptoms and a much smaller fraction of people (less than one in 100) develop more serious symptoms including paresthesia (feelings of pin and needles in legs), meningitis (infection of the covering of the spinal cord and/or brain) and paralysis. Among those paralyzed, 5% to 10% die when the virus affects their breathing muscles.
Back in the day, even those who did recover faced lifelong challenges. The World Health Organization has reported on some of the disease’s consequences: Deformed limbs meant many needed leg braces, crutches or wheelchairs, and some needed to use breathing devices like the iron lung, an artificial respirator invented for treatment of polio patients. To add insult to injury, some children went on to develop post-polio syndrome decades later, which can include muscle weakness, joint pain and feelings of mental and physical fatigue.
But then came the polio vaccine, which provided high levels of protection and through our collective herd immunity, we have been able to fend off the virus (though pockets of vulnerability remain in our communities where there are low vaccination rates).
Wild poliovirus remains endemic in Pakistan and Afghanistan. Though polio cases have decreased worldwide by nearly 99%, the virus remains at large in those two countries and the threat of imported cases of polio continues to exist.
During my trip to Pakistan in 2018, I spoke with officials from Pakistan’s National Institute of Health on the importance of biopreparedness for emerging and reemerging infectious disease threats. I remember driving through the ancient city of Multan, where more recently, thousands of Pakistani children were vaccinated against polio in 2020, and thinking how difficult vaccination efforts are in many of these remote areas.
So, it comes as no surprise when public health officials are worried when polio is diagnosed or detected in wastewater surveillance, signaling a larger, local outbreak is occurring. The risk to the public is low as most people are protected from their childhood polio vaccinations. However, people most at risk for infection include those who are unvaccinated or under-vaccinated.
London is facing similar concerns to New York’s; poliovirus was discovered in the city’s sewage in June. The UK Health Security Agency (UKHSA) has responded with an unprecedented move, and one highlighting the urgency of the situation: Around 1 million children under the age of 10 in London will be offered polio booster vaccines as a precautionary measure. According to Dr. Vanessa Saliba, consultant epidemiologist at the UKHSA, “The areas in London where the poliovirus is being transmitted have some of the lowest vaccination rates.”
These latest polio incidents are not one-off events. Immunization coverage is dropping worldwide, and the immunity wall generations past have built is slowly being chipped away. The vaccine distrust that unwarrantedly grew out of the Covid-19 pandemic is only driving more people to opt out of vaccinations or under vaccinate themselves and their children. Others may have paused or delayed vaccination programs due to disruptions caused by the pandemic. The latest report by the World Health Organization shows global immunization coverage – including the polio vaccine along with numerous others like measles and rubella – dropped from 86% in 2019 to 81% in 2021.
As the WHO puts it, “as long as a single child remains infected with poliovirus, children in all countries are at risk of contracting the disease. The poliovirus can easily be imported into a polio-free country and can spread rapidly amongst unimmunized populations.”
Polio should have been a disease relegated to the pages in our history books. It is human behavior and the choices we make that prevent it from become another lasting public health success story.
