US’s Reactive Polio Strategy Could Be Silently Putting Many at Risk

About a month ago, British health authorities announced they’d found evidence suggesting local spread of polio in London.

It was a shock, it was true. In 2003, the country was declared polio-free.

However, no one was actually sick. Routine tests of sewage samples provided proof that the virus was present. This can alert health officials to the possibility and allow them quickly to respond. Based on genetic analysis of those samples, officials in the United Kingdom moved to protect the city’s children by reaching out to families with kids under 5 who hadn’t been fully vaccinated.

Polio’s first appearance in almost a decade in the U.S., confirmedAccording to New York health officials, the outcome would be quite different as announced late last week.

In the U.S., public health agencies generally don’t test sewage for polio. Instead, they wait for people to show up sick in doctor’s offices or hospitals — a reactive strategy that can give this stealthy virus more time to circulate silently through the community before it is detected.

The first sign of trouble in New York was when a young man from Rockland County sought medical attention for weakness and paralysis. Nearly a month had passed before tests confirmed that he had polio.

Because the majority of polio infections cause no symptoms, by the time there’s a case of paralysis, 100 to 1,000 infections may have occurred, said Dr. Yvonne Maldonado, a professor of pediatrics at the Stanford School of Medicine who chairs the American Academy of Pediatrics’ committee on infectious diseases.

“You’re already chasing your tail if you’re going to wait for a case to show up,” she said.

New York’s health officials started the same surveillance as the British, testing wastewater samples from Rockland County to see if the virus was spreading. New York, like many other parts of the U.S.A., was already collecting sewage and analysing it to track the spread COVID-19. Health officials say they’re now testing stored samples for signs of polio. They say they’ve detected polio in a few Rockland County samples but need to analyze more to understand what the initial results represent.

For decades, the cost to monitor wastewater for diseases like Polio was clearly greater than the benefit.

High U.S. vaccination rates (over 90%) have made the risk of such diseases extremely low. However, there are long been areas where rates are much lower. Rockland County is a suburb northwest of New York City. It was hit by severe flooding. an extended outbreak of measlesAnother vaccine-preventable disease was polio in 2018 and 2019. It was mainly concentrated in the Orthodox Jewish community. Many opt out of vaccines. Numerous news organizations have reportedThe polio patient is part of that community.

There are indications that the pandemic has created new vulnerabilities to diseases that were long in retreat, both nationally and globally. Routine immunizations are being hampered by a number of obstacles. These include COVID-19-related restrictions and growing vaccine resistance, fueled by misinformation. A recent analysis by UNICEF and the World Health Organization showed that the percentage of children worldwide who received all three doses of the vaccine against diphtheria, tetanus and pertussis — a measure of overall immunization — dropped 5 points between 2019 and 2021 and that measles and polio vaccinations fell, too. The organizations say that’s the largest sustained decline in childhood vaccinations in the roughly 30 years they’ve been collecting data.

This could increase the risk of contracting polio, which has been a major problem in the United States for the first half century. Polio is a highly contagious disease that can be life-threatening and can affect young children. It attacks the spinal cords, brain stems, or both.

The virus spreads when fecal material or respiratory droplets from infected people get into water or food or onto other people’s hands, which they then put into their mouths. This may sound unusual, but it’s among the more common ways viruses circulate, especially among children.

Around 70% of people infected do not show any symptoms but can spread the disease to others. Most people who get sick have mild symptoms like a sore throat, muscle weakness, nausea, and fever. But about 5 in 1,000 infected people develop irreversible paralysis.

In 1952, polio claimed more than 3,000 lives and paralyzed over 20,000 people. Parents were terrified to see their children in iron lungs that resembled coffins. Those fears vanished quickly after the 1955 approval for the first polio vaccination. Within two years, cases dropped as high as 90%.

The Global Polio Eradication Initiative has invested billions in immunization campaigns around the globe since 1988. This is when polio was almost eradicated. Wild polio, which is the type that occurs naturally, is still endemic in two countries, Pakistan, and Afghanistan.

But there’s another kind of polio that’s circulating, one linked to the type of vaccine that’s used in much of the world, particularly lower-income countries. This oral vaccine, which hasn’t been used in the U.S. since 2000, is easy to administer — just a few drops on the tongue — and cheap to make. It triggers the immune system to produce protective antibodies by using weakened live viruses.

This brings us a bonus. The weakened viruses in the stool of the vaccinated can spread to those who are not vaccinated. This triggers protective antibodies.

It also comes with a risk. Rarely, the weakened virus can revert back to the original form in people who have not received the vaccine or aren’t fully vaccinated. This can lead to the spread of the disease that they were intended to prevent. The injectable vaccine against polio in the USA contains only inactivated viruses, and cannot cause it.

Since 2016, global health authorities have seen an increase in cases of vaccine-derived polio. decided to removeAfter determining that the wild strain of polio had been eliminated globally, the oral vaccine was able to eliminate one strain. The result was that a growing number children were left with polio. no immunityType 2. is the vaccine-derived version. (The U.S. vaccine injectable form provides protection against all polio strains.

Type 2 vaccine-derived Poliovirus was the type that was found in British sewage samples. Health officials in New York confirmed that it also infected the Rockland County man who was not vaccinated. This suggests that the virus could have spread from someone who received the oral vaccine.

Officials are still investigating how the virus was transmitted to the man, whether it is here or abroad. The Washington Post reported that the man traveled to Poland and Hungary this year, but a spokesperson for the Rockland County Health Department said in an email, “The person did not travel outside the country during what would have been the incubation window.”

Ultimately, New York health officials will use wastewater monitoring to tell them quickly whether they have a bigger problem, essentially allowing them to test thousands of people at once for polio infection rather than individually, David Larsen, an epidemiologist and Syracuse University professor who directs the state’s wastewater surveillance network, said in an email.

For decades, wastewater testing for polio was a common practice in developing countries. However, it is still a popular method of testing for the disease.

A spokesperson for the British health security organization said via email that the U.K. started monitoring wastewater for polio in 2016. (It has since added COVID-19 virus to the list.

Since 1989, Israel has been monitoring the sewage for signs of polio. In 2013, health officials were capable of detecting a wild polio outbreak by sampling the water and launched a vaccine campaign to combat it. No paralysis was ever reported. A young child from the Jerusalem area was diagnosed with paralytic polio this year. Additional infections were discovered by sewage tests, according to public health officials.

Some U.S. public-health officials are skeptical about the validity of such testing.

“I’ve always been unenthusiastic about doing it for polio in the U.S. and a big supporter of doing it elsewhere, where there are deficiencies in other surveillance systems,” said Mark Pallansch, who retired in 2021 after spending much of his career working on polio eradication efforts for the Centers for Disease Control and Prevention.

COVID-19 has sparked a flurry of interest in wastewater surveillance. This has prompted cities, states, and colleges to launch programs, and opened a floodgate for funding.

The CDC sent federal money to health departments in over 40 jurisdictions to support such tracking efforts, working with them to collect data that’s published on the agency’s National Wastewater Surveillance System website. In an email, a spokesperson for the CDC stated that they were working to expand the platform to include data regarding other pathogens. This includes foodborne diseases like salmonella and influenza. However, not polio. According to the spokesperson, testing for polio nationally would require more resources and labor, which would necessitate an increase in public health laboratory capacity.

One advantage of wastewater monitoring is its ability to quickly pivot to test something new.

The Sewer Coronavirus Alert Network, which is based at Emory and Stanford universities, began daily monitoring of California wastewater plants for COVID-19 in November 2020. It’s since added monitoring for other pathogens, including COVID-19 variants, the common respiratory virus RSV and, most recently, monkeypox. These additions are relatively cost-effective as the network can test multiple pathogens from one sample, according to Marlene Wolfe, one of two principal investigators at Emory’s Rollins School of Public Health.

Wolfe said that while adding more tests is an option, the question is always if monitoring a disease in this way will raise enough concern to make public health decisions.

Many question whether the rapid expansion of wastewater testing that was fueled by the pandemic is sustainable. Maldonado, the American Academy of Pediatrics’ infectious diseases committee chair, said the recent polio case is another signal that more disease tracking is critical.

“Maybe this is a clarion call for us to really start building better surveillance networks,” she said.