Polio: What nurses need to know

Submitted by njones on
Polio iron lung

What is polio?

Poliomyelitis, commonly referred to as polio, is a highly contagious viral disease that primarily affects the central nervous system. Polio was a feared disease of major public health concern in the 20th century until the creation of an effective vaccine in the 1950s.

Globally, wild poliovirus cases have decreased by over 99 percent since 1988, from an estimated 350,000 cases in more than 125 endemic countries to 99 reported cases in 2024. Now, polio remains endemic in only two countries, Afghanistan and Pakistan.

There are three types of wild poliovirus: type 1 (WPV1), type 2 (WPV2), and type 3 (WPV3). WPV1 is the only strain still circulating, as WPV2 and WPV3 were eradicated worldwide in 1999 and 2020, respectively. While cases of wild poliovirus have decreased significantly over the decades, the number of cases in 2024 were 725% higher than in 2023.

What is the status of polio in the United States?

While there have been no cases of wild poliovirus in the U.S. since 1979 (with the last imported case occurring in 1993), the U.S. Department of Health and Human Services is facing drastic budget and staffing cuts that will hinder the ability of agencies like the CDC to respond to imported cases, increasing the likelihood of local outbreaks. Cuts to the U.S.’s public health infrastructure will result in delayed and disrupted responses to disease outbreaks both at home and around the world, undermining our ability to prepare and adequately respond to future pandemics.

In January 2025, the current administration withdrew the U.S. from the World Health Organization (WHO), compromising the CDC’s longstanding partnership in the WHO-led Global Polio Eradication Initiative (GPEI). Our nation’s departure from the WHO will not only limit the information we receive about global health threats and impede on our domestic response, but also exacerbate global health crises, as the U.S. has often lent expertise and support to stop international disease outbreaks. Health care facilities must consequently be prepared to identify, treat, and control any cases of polio.

What are the symptoms and complications of polio?

Most people infected with poliovirus are asymptomatic. About 25 percent of patients will have flu-like symptoms that can last two to five days, including:

  • Sore throat,
  • Fever,
  • Tiredness,
  • Nausea,
  • Headache, and
  • Stomach pain.

Neurological symptoms affecting the brain and spinal cord will develop in a smaller percentage of individuals:

  • Meningitis occurs in about one to five percent of patients.
  • Paralysis occurs in less than one percent of patients and can lead to permanent disability or death. Two to ten percent of patients with paralysis die due to the immobilization of their lungs and the inability to breathe.

The incubation period for polio from exposure to symptom onset ranges from three to six days for nonparalytic symptoms, and seven to 21 days for paralysis.

Post-polio syndrome (PPS) is estimated to occur in 25 to 40 percent of adults who survived paralytic polio in their childhood. PPS is characterized by worsening muscle weakness and joint pain 15 to 40 years after initial infection.

How is polio transmitted?

Poliovirus is widely thought to be spread from human-to-human through the fecal-oral route, based on research from the 1940s and 1950s. However, other mechanistic pathways—not considered in early research—exist where the virus may be transmitted via the respiratory route. There is also strong epidemiological evidence that suggests that poliovirus can be transmitted via inhalation.

Poliovirus can multiply in a person’s throat and intestines. The virus is usually present in respiratory secretions for one to two weeks and can be shed in stools for several weeks after infection, even in individuals with minor symptoms or no illness. An infected person—regardless of whether they are symptomatic or asymptomatic—can spread the virus to others for weeks after symptoms first appear.

Current guidelines on poliovirus fail to acknowledge the lack of scientific consensus surrounding poliovirus transmission and pathogenesis. Potentially misleading assumptions made in the last century continue to guide polio infection control and prevention. Under the precautionary principle and based on the available scientific evidence, it is important that both the fecal-oral and respiratory pathways are considered when caring for a patient with polio.

Is the polio vaccine safe?

The elimination of wild poliovirus in all but two countries can be attributed exclusively to the polio vaccines, which are estimated to have saved 1.5 million lives and prevented over 20 million cases of paralysis worldwide since 1988. Three doses of the inactivated polio vaccine (IPV)—which contains a killed version of the virus and cannot cause polio—are 99 to 100 percent effective against polio. The IPV is the only polio vaccine that is licensed and available in the U.S. since 2000.

The IPV was created by U.S. physician Jonas Salk in the early 1950s. Salk championed equitable access to the vaccine by making his vaccine freely available to the public—instead of profiting from it. In a 1955 interview, when asked who owned the patent for the IPV, Salk replied: “Well, the people, I would say. There is no patent. Could you patent the sun?” Salk knew that low- to no-cost vaccines were essential in achieving disease elimination. His decision not to patent the IPV allowed for its rapid and widespread distribution and, subsequently, the significant decline in cases worldwide.

What is the difference between wild and vaccine-derived poliovirus?

Vaccine-derived poliovirus is caused by a strain related to the weakened, live poliovirus contained in the oral polio vaccine (OPV), which has not been administered in the U.S. since the turn of the 21st century. Vaccine-derived poliovirus cases arise when immunization rates are insufficient, allowing the weakened virus from OPV to spread among unvaccinated or under-vaccinated communities. If the virus circulates in these populations for an extended period, or replicates in individuals with weakened immune systems, it can mutate and revert to a form that causes illness and paralysis. Vaccine-associated paralytic poliomyelitis (VAPP) is extremely rare and occurs at a rate of approximately one in 2.7 million doses.

In 2022, a case of VAPP was reported in an unvaccinated man in Rockland County, New York, an area with very low vaccination rates. Public health agencies began wastewater surveillance upon notification of the case and found that eight percent of the wastewater samples (21 of 260 samples) tested positive for poliovirus. Transmission via the fecal-oral route was ruled out, which supports the role the respiratory tract likely plays in transmission.

What protections do nurses and other health care workers need to care for a patient with suspected or confirmed polio?

There is no cure for polio and infection bears the risk of paralysis and death. While the vaccine is the best way to prevent polio, declining vaccination rates increase the risk of imported cases and outbreaks in the U.S. Health care employers are responsible for providing a safe work and patient care environment and must be prepared to implement a multifaceted, robust infection control strategy.

Multilayered infection prevention measures based on the available scientific evidence and the precautionary principle should be implemented in all health care facilities experiencing suspected or confirmed polio cases, including:

  • Patient and visitor screening – Screen patients and visitors before or immediately upon arrival at the facility to ensure prompt identification and diagnosis. Delays in identification of patients with possible polio infections can lead to preventable exposures.
  • Isolation and source control – Patients with suspected or confirmed polio should be isolated promptly in an airborne infection isolation room with its own bathroom. The WHO recommends that patients be isolated until three negative stool samples are collected on three consecutive days.
  • Ventilation – Adequate ventilation is essential for reducing the risk of transmission in lobbies, waiting rooms, exam rooms, treatment areas, and other areas of the facility where a suspected or confirmed case could be present before being identified and isolated.
  • Hand Hygiene – Wash hands using soap and warm water. Note that alcohol-based hand sanitizers are ineffective against poliovirus.
  • Personal protective equipment – Use a respirator, gloves, face shield or goggles, and a gown or coveralls when caring for patients with confirmed or suspected poliovirus or when handling contaminated materials.
  • Environmental cleaning – Clean surfaces with disinfectants that contain free chlorine, such as sodium hypochlorite or bleach. Bleach in concentrations lower than 52 percent have been found to be ineffective against poliovirus. Follow the manufacturer’s instructions, as contact time is important in inactivating the virus.
  • Proper linen and waste disposal – Handle and dispose of contaminated linens and waste carefully and using precautions necessary to prevent further transmission. Non-disposable laundry should be soaked in chlorine bleach (diluted according to the manufacturer’s instructions) for at least 15 minutes. Find more information on cleaning and disinfection in the WHO’s guidance on managing PV exposure.
  • Training and education – Training and education should be provided to all staff who might encounter a possible polio patient, including in the emergency departments, clinics, triage, admitting and registration, and other areas. Training should include information on current polio outbreaks, how to recognize possible polio cases, and the employer’s exposure control plan to prevent polio exposure.
  • Exposure notification and contact tracing – When a polio case is identified, employers should conduct contact tracing and immediately notify staff who were potentially exposed. Exposure should include both direct contact while providing care and sharing air space (e.g., being in the same waiting room, triage station, etc.).
  • Paid vaccinations – Employers should provide access to vaccines at no cost to the employee for any nurse or other health care worker that is not already vaccinated.
  • Paid precautionary medical removal – Employers should provide paid precautionary medical removal for any nurse or other health care worker who is removed from the workplace due to occupational exposure or infection with polio.