Fear of a Polio Outbreak Brewing in New York

SARS-CoV-2, monkeypox, multidrug-resistant pathogens, and now the shocking return of polio virus. “Bring it on,” said no infection preventionist ever.

No, infection control was quite difficult enough, thank you, before a recent paralytic polio case in New York brought back memories of the terror of post-war America, when a mysterious disease with no treatment nor vaccine began spreading by unknown routes of transmission.

Polio was declared eradicated in the United States in 1979, but sporadic introductions have occurred since then. However, the latest case in New York contracted the virus locally in what appears to be a potential outbreak.

The Centers for Disease Control and Prevention (CDC) is investigating a case of paralytic polio in an unvaccinated, immune-competent young patient who presented to an emergency room in Rockland County, NY, with lower limb weakness and fever.

“Vaccine-derived poliovirus type 2 was confirmed by the CDC and the sequence showed 10 nucleotide changes in the region that encoded viral capsid protein 1 — as compared to the Sabin 2 strain — which might imply circulation for some time and reversion to capability of causing paralysis,” said Emily Lutterloh, MD, MPH, epidemiology director at the New York State Department of Health.

Speaking at a CDC clinical briefing, Lutterloh said the patient did not have any international travel during the 21-day incubation period before the onset of paralysis, but had attended a large gathering about eight days before the onset of symptoms.¹

“Generally, person-to-person spread occurs via the fecal-oral route,” the CDC’s Farrell Tobolowsky, DO, MS, LCDR, said at the clinical briefing. “However, it can spread less commonly through the oral-to-oral route or contamination of food or water and unsanitary conditions. Patients are most infectious during the days immediately before and after the onset of symptoms. But they can shed the virus in their stool on average for three to six weeks and sometimes longer. Most importantly, even those with asymptomatic or mild infection, can shed the virus.”

The dramatic presentation of paralytic polio occurs in only about 1% of cases, when destruction of spinal tissue induces loss of limb function. Referring to this spine damage, poliomyelitis is derived from the Greek for “gray marrow.”

“One case of paralytic polio indicates an outbreak and there are likely many infected, with about 25% having a mild clinical illness and the majority — about 75% — having an asymptomatic infection,” Tobolowsky said.

The CDC does not routinely test wastewater for poliovirus but began doing so after discovering the paralytic case.² Poliovirus was found in sewage in Rockland County and two adjacent counties, as well as in New York City to the south.

The virus found in Nassau County on Long Island was a genetic match to the index case, suggesting clonal spread in the region.

Emergency Declared

On Sept. 9, 2022, New York Governor Kathy Hochul declared a state of emergency prioritizing polio vaccine distribution and expanding those who can administer it to include emergency medical workers, midwives, and pharmacists.

“Routine vaccination rates against polio across all ages have decreased throughout the COVID-19 pandemic, and vaccine hesitancy has increased,” Hochul’s executive order states.³ “The vaccination rate against polio among 2-year-old children in New York [state] is 79% — and is significantly less than that in several counties and ZIP codes.”

The CDC and the state are collaborating to increase surveillance of cases and contact tracing. Trying to detect the level of asymptomatic polio, investigators are working with pediatricians to obtain samples from soiled diapers, if the parents of the child agree.

“We’ve also recommended boosters for a very narrow group of individuals who are at high-risk exposures, such as those in contact with our case and certain healthcare workers who might care for polio patients,” Lutterloh said.

The New York patient contracted a strain of vaccine-derived poliovirus, which is the weakened live poliovirus contained in oral polio vaccine. “If allowed to circulate in under- or unimmunized populations for long enough, or replicate in an immunodeficient individual, the weakened virus can revert to a form that causes illness and paralysis,” the CDC noted.⁴

The United States has used inactivated polio virus vaccine via injection since 2000, but the oral immunization still is used in other parts of the world and generally is effective unless overall immunity begins to ebb.

The return of polio, even in a single case, recalls a public fear of the paralytic disease in post-war America that is hard to overstate. People were afraid to go out and gather at theaters and the like, so social distancing is not new. With one prevailing theory that it was spread by flies and mosquitoes, suburban yards with soaked with dichlorodiphenyltrichloroethane (DDT), which was later determined to be toxic. A survey of Americans in 1952 found that only nuclear annihilation was more feared than polio.⁵

Polio cases peaked that year at 58,000, with about 3,000 deaths. However, Jonas Salk, MD, was hard at work on a vaccine in his University of Pittsburgh laboratory. Salk killed strains of the virus and injected them into research monkeys and other animals, theorizing correctly that the experiment would generate an immune response and prevent poliomyelitis. He was right and became so convinced of the efficacy and safety of the vaccine that some of the first humans who were immunized in 1953 were Salk and his family.

REFERENCES

1. Centers for Disease Control and Prevention. Polio in New York: How to recognize and report polio, and reinforce routine childhood polio vaccination. Published Sept. 1, 2022. https://emergency.cdc.gov/coca/calls/2022/callinfo_090122.asp
2. Sun LH. Community spread of polio prompts CDC wastewater surveillance. The Washington Post. Published Sept. 15, 2022. https://www.washingtonpost.com/health/2022/09/15/polio-virus-wastewater-cdc/
3. Governor Kathy Hochul. Executive Order 21: Declaring a disaster in the State of New York. Sept. 9, 2022. https://www.governor.ny.gov/executive-order/no-21-declaring-disaster-state-new-york
4. Centers for Disease Control and Prevention. Vaccine-derived poliovirus. Updated Aug. 3, 2022. https://www.cdc.gov/vaccines/vpd/polio/hcp/vaccine-derived-poliovirus-faq.html#:~:text=If%20allowed%20to%20circulate%20in,that%20causes%20illness%20and%20paralysis
5. Janssen V. When polio triggered fear and panic among parents in the 1950s. History.com. Updated April 2, 2020. https://www.history.com/news/polio-fear-post-wwii-era