In the mid-twentieth century, the poliomyelitis epidemic was so severe in the United States that tens of thousands of people were paralyzed by it every year. Once virologist Dr. Jonas Salk created an effective vaccine in 1955, however, those numbers began to drop. Since 1979, there has not been a single case of wild poliovirus originating in the United States. (Some cases of wild poliovirus were brought to the United States from other countries.) Even today, cases of polio of any kind in this country are extremely rare.
Yet a new wave of polio cases in New York state suggests that polio outbreaks are no longer as rare as they once were in the United States.
A federal team of scientists was sent to new york by the Centers for Disease Control and Prevention (CDC) to investigate what appears to be a string of polio cases in the state. It all started in Rockland County, where a once-healthy young adult saw his legs paralyzed after developing the first case of polio seen here in nearly a decade. This patient is believed to have received polio from an oral vaccine, the type of which is no longer given in the United States but is still used outside the country. The oral vaccine uses a weakened live version of the poliovirus.
News of a polio outbreak in the United States is unprecedented given the state of near-eradication of the disease. Polio vaccines are a standard complement to vaccines issued in the US health care system; most children in the United States are received four polio vaccines between birth and 6 years of age, as recommended by the Centers for Disease Control and Prevention (CDC). The CDC States that “almost all children (99 out of 100)” who receive these recommended vaccines will be protected against the poliomyelitis virus.
Since the outbreak in New York State, experts have also been testing sewage in New York’s Rockland County and its neighbor Orange County. Much to their dismay, the scientists found three sewage samples that tested positive for polio, along with four others that were genetically linked to the previously confirmed case. Because a the majority of people with polio do not develop any symptoms and many polio patients simply develop flu-like symptoms rather than paralysis, this suggests that there could be other infected people who simply don’t know they are infected.
Given how rare polio is today, the polio epidemic in New York is particularly worrisome. Indeed, the burst of anti-vaccination conspiracy theories who have played a significant role over the past two decades have caused millions of Americans to avoid vaccinating themselves or their children due to misinformation. The specter of vaccine misinformation hangs over any outbreak of a nearly eradicated disease.
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Yet, given the importance of polio vaccination, could an outbreak really spread beyond a small area like these two New York counties? Notably, polio vaccination rates in Rockland and Orange County are respectively 60.34% and 58.68%. That ranks them all the way down: Of New York’s 62 counties, only one, Yates County, had a lower polio vaccination rate.
In other words, the polio outbreak could very well be linked to anti-vaccination attitudes in rural Rockland County. Indeed, in addition to the possibility that the Rockland County patient contracted poliomyelitis because he took an oral vaccine, Rockland County a large Hasidic Jewish community which has sometimes harbored anti-vaccination sentiments. Like The Times of Israel writinga “fierce backlash against vaccination” exists in some Orthodox communities, “fueled by the COVID-19 pandemic and following a measles outbreak in Rockland County in 2018 and 2019 that was centered on the haredi Orthodox population of the region”.
“The risk of spreading polio is limited to those who have not received the polio vaccine,” Russell Medford, president of the Center for Global Health Innovation, told Salon via email. “According to the CDC, in the United States, nearly 93% of children are vaccinated by age [two].”
In 2018 and 2019, a group of Hasidic rabbis in this county experienced a measles outbreak linked to anti-vaccination tendencies in their community that prevented herd immunity; measles is preventable with vaccines. Political leaders in Rockland County hinted at it last month.
“Our people have overcome measles, and I’m sure we’ll eliminate the last health issue as well,” County Executive Ed Daly said at a July 21 news conference.
If you’re worried these polio outbreaks could lead to a bigger pandemic, health experts say if you got your polio shot in the United States, you’re almost certainly safe.
“The risk of spreading polio is limited to those who have not received the polio vaccine,” said Russell Medford, President of the Center for Global Health Innovation, Salon said via email. “According to the CDC, in the United States, nearly 93% of children are vaccinated by age [two].”
Dr. Al Sommer, Dean Emeritus and Professor of Epidemiology at Johns Hopkins Bloomberg School of Public Healthexpressed a similar opinion.
“It can certainly spread — infect someone without causing disease, but be excreted by them and therefore ‘transmitted,'” Sommer told Salon via email. “But it would be rare for a vaccinated person to become clinically affected even if they encountered the virus.”
It should also be noted that poliomyelitis vaccine is considered to confer lasting immunity, meaning it lasts a long time with just the initial inoculation. This contrasts them with COVID-19 vaccines, which are still extremely effective but require more regular injections to keep up with new strains. This type of immunity is called transient immunity; influenza is an example of another virus for which infection or vaccination confers only transient or short-term immunity.
As Dr. Monica Gandhi, an infectious disease physician and professor of medicine at the University of California, San Francisco, has said, there are two types of polio vaccines, which work very well and provide long-lasting immunity. “Both types of vaccines confer long-lasting immunity against disease development,” Gandhi said.
That said, as Sommer noted, there is still room for caution.
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” He can still be an epidemic if the virus is widespread in a largely unvaccinated community,” Sommer explained.But, since most Americans have been fully vaccinated in the past, it is unlikely to overtake the unvaccinated community or cause anything like COVID in the United States. Given the nature of the polio virus (and its many variants) and the effectiveness of the polio vaccine (live and killed versions), we should not expect a remote epidemic or pandemic like the COVID pandemic.”
“Based on past polio outbreaks, New Yorkers should know that for every case of paralytic polio observed, there may be hundreds more infected.”
If another major epidemic occurs, it could be devastating. During the mid-20th century polio epidemic in the United Statestens of thousands of people were paralyzed until Dr. Jonas Salk released his polio vaccine in 1955. Even after that, however, those thousands of people lived with the ramifications of the disease for the rest of their lives. life – and helped launch the disability rights movement in the process.
This lingering memory may explain why public health officials are also warning of the potential for a larger outbreak.
“Based on past polio outbreaks, New Yorkers should know that for every case of paralytic polio observed, there may be hundreds more infected,” explained the state health commissioner, Dr. Mary T. Bassett, in a statement.
Bassett added, “Coupled with the latest sewage findings, the Department is treating the single polio case as the tip of the iceberg of a much larger potential spread. As we learn more, what we know is clear: the danger of polio is present in New York City today.”
The CDC reassured the public that it was doing its best to stay informed about the potential pandemic.
“The CDC continues to work with the New York State Department of Health to investigate their recent polio case, including ongoing testing of sewage samples to monitor poliovirus and the deployment of a small team in New York to assist on the ground with investigative and vaccination efforts,” a CDC spokesperson told reporters on Sunday.
It should be noted that the sample from the infected patient from Rockland County shows genetic similarity to samples found in sewage from Jerusalem and London, Israeli and British cities respectively. This suggests that the poliovirus in question did not originate in the United States, although this is not certain.
The news also raises awareness of one of the common criticisms leveled at the Albert Sabin vaccine, which, although generally effective, can in rare cases produce a virus that mutates, regains its virulence and causes infections symptomatic of poliomyelitis. Most of the current cases of poliomyelitis around the world have been caused by this vaccine, and in particular by a process that causes the virus to mutate into its most dangerous form when passing through a patient’s intestine.
This type of poliovirus, known as type 2, cripples as few as 1 in 1,000 people who catch it. Many others will only display symptoms like diarrhea and a runny nose and conclude they are sick with something more harmless.