Wait, Why Are We Talking About Polio?
A case of paralytic polio strikes New York City, which is bad but not as bad as it could be.
When I heard that there was polio in New York, my heart skipped a beat. I knew that we had recently come wonderfully close to eradicating polio, and I knew that there was concern that the disruption of medical services during the COVID pandemic might lead to a resurgence of polio. Still, I hadn’t been paying particularly close attention to it until I heard about the case of paralytic polio in Rockland, New York.
I’m not going to lie; I panicked. It reminded me of the story of the last smallpox outbreak ever in the United States. As related by DA Henderson in his book “Smallpox: The Death of a Disease”:
Smallpox suddenly appeared in New York City—two smallpox patients were discovered, but no one knew how or where they had acquired the infection. Their movements were traced, and more smallpox patients were discovered. Emergency vaccination programs began—first for the hospital staff and the patients where the cases were isolated and then for residents of the apartments where they had lived. As more smallpox patients were found, the vaccination program extended to other hospitals and to other parts of the city. Eventually, the source was discovered: a visitor from Mexico who had become ill and died five days after his arrival. During his stay in a hotel, 3,000 people from twenty-eight states had booked rooms. Health staff sought to trace and vaccinate all of them. The city was in turmoil. A decision was finally made to vaccinate the entire urban population. Six million people were vaccinated during a four-week period. This massive effort was the response to an outbreak that consisted of only twelve patients, two of whom died.
My initial reaction to this was that we need to treat this reintroduction of polio with the same near-panicked urgency. This sense was heightened when I learned that polio had been detected in wastewater in New York, the United Kingdom, and Israel. This is starting to sound like a grave emergency, and we need to respond to this with the highest possible urgency!
I started researching this case and the status of polio across the world and I wanted to relay the larger context of what I learned. It was both encouraging and concerning.
So Many Polios
There are several kinds of polio. There are three wild strains (serotypes) of polio, creatively named type 1, type 2, and type 3. They are distinguished thus because immunity from one type does not provide immunity from the other types. Fortunately, type 2 and 3 have been eradicated, with zero cases detected since 1999 and 2012 respectively. Type 1 is still in circulation, but since 2016 the only polio cases have been found in Afghanistan and Pakistan and in 2019 that number was under 200.
The polio case that paralyzed the young man in New York was not a wild poliovirus, but a strain of polio known as a “vaccine-derived poliovirus” or VDPV.
So… wait. The use of polio vaccines can lead to paralytic polio? Yes, but only a specific kind of vaccine and these cases are not caused directly by the vaccine. We need to back up a little bit to explain how the polio vaccines work and how someone can catch a case of VCPV.
There are two kinds of polio vaccines. The first is the injected inactivated polio vaccine (IPV) preferred in most first-world counties. This vaccine protects against polio but does not cause the patient to become infected with polio. The antibodies are generated but the patient does not shed any virus that can infect others.
The second polio vaccine is the oral vaccine. This vaccine contains a live weakened polio virus that can replicate in the patient’s gut. Patients can then shed the virus and this shedding can infect other unvaccinated individuals with the weakened virus.
This weakened virus can, over time and through a large number of transmissions, revert to a form that can paralyze the host. This typically takes about 12-18 months and is most common in populations with low polio vaccination rates. This typically happens with the component of the vaccine related to type 2 polio. Given that we think type 2 polio is eradicated, there has been some debate about removing the type 2 component from the oral vaccine in order to reduce the risks of future VDPV.
But if this risk is so well known, why would we even use the oral vaccine? Well… we don’t, at least not in the United States. We have been using the IPV with few exceptions for decades. However, the oral vaccine is still frequently used in many other countries because it does not require an injection, making it easy to administer and increasing uptake.
The reports of a case of paralytic polio in New York were from an unvaccinated individual infected with the vaccine-derived poliovirus. It seems like this probably came from an infection in Israel, though it might have arrived there from a case in the UK. To my knowledge, there has not been any success tracking this outbreak any further back.
This would not be the first time this has happened; we’ve had at least three outbreaks of VDPV in the United States in the past 20 years. But it is incredibly concerning given that routine vaccinations in children have plummeted in the wake of the COVID pandemic. Polio vaccination rates for young children in New York range from 92% to 53%, depending on the county.
That is a lot of potential risk.
Return of the Sane Public Health Response
The appropriate response to polio is a nearly perfect counter-example for the recent response to COVID. Polio has a vaccine with a decades-long safety record, protecting children against a disease that disproportionally impacts them. If kids are caught up on their standard vaccination schedules, they should be protected.
It seems that the UK is treating its recent outbreak as a high-level emergency. Their response has been to increase sewage surveillance and prioritize vaccinations and boosters for children under 10 in London. They have named every borough that has seen a positive sample of poliovirus to give parents a sense of where the urgency is most needed.
This strikes me as the appropriate response. It is urgent but doesn’t inspire panic. It is focused and informative. I can read that response and know what my next steps are and what the risks will be.
Importantly, this response does not isolate or harm anyone. It doesn’t mandate anything. Despite the risks, this public health response doesn’t close anything or interfere with lives. It provides a few proactive steps and gives citizens all the information they need to make their own choices.
Disney Shorts: The Country Cousin (1936)
This is really funny to me because it’s such a counter-balance to so much of Disney’s typical message of the value of country life.
Money Citymouse writes to his cousin Abner Countrymouse (who lives in Podunk) the following message: Stop being a hick, come to the city and live in splendor.
Throughout this short, the city mouse is bright, sophisticated, and savvy while the country mouse is something of a buffoon. The country mouse knocks on the wrong door, almost gets killed by a mousetrap, becomes recklessly drunk, and generally embarrasses and inconveniences his long-suffering cousin.
There never is any redemption for the country mouse. He doesn’t prove himself good at some country virtue which his city cousin lacks so that they might understand how complimentary values might work. He just gets scared and runs back to Podunk.
All in all, it’s still a funny short. It’s just funny to see a Disney short show a country bumpkin so completely devoid of talents or redeeming qualities.