Poliovirus Detections

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Last reviewed
February 28, 2024
Content Overview
Poliovirus wastewater detection in Montreal, New York, and England in 2023. Polio vaccine information fact-checked by medical professionals.

Poliovirus Detections

The World Health Organization (WHO) confirmed that in 2024, the spread of poliovirus remained a Public Health Emergency of International Concern (PHEIC). Poliomyelitis has been confirmed in wastewater and ground samples in Africa, the AmericasAsia, CanadaEurope, India, Israel, the United Kingdom, and New York in 2023. The total number of poliomyelitis samples collected in countries with poliovirus transmission was 12,259 from 40 countries in 2022, an increase from 8,945 in 36 countries in 2021.

Vaccine-Derived Polioviruses (VDPVs)

Vaccine-derived polioviruses (VDPVs) can emerge from Sabin strain poliovirus serotypes 1, 2, and 3 contained in the oral polio vaccine (OPV), which induces a transmission-blocking response. However, low population immunity allows OPV to circulate for long enough to lose its attenuating mutations, regaining transmissibility and pathogenicitiy similar to wild poliovirus, resulting in outbreaks of circulating vaccine-derived poliovirus (cVDPV). As most cVDPVs have been type 2 and wild-type 2 poliovirus had been eradicated, type 2 OPV (OPV2) was withdrawn from routine immunization in 2016. Outbreaks of cVDPV2 required responses using monovalent type OPV2 (mOPV2), leading to more than 70 new emergences of cVDPV2 and cycles of outbreaks and responses. Since 2016, more than 3,000 cVDPV2 cases have been reported, with 75% linked to outbreak responses with Sabin OPV.

Poliovirus Wastewater Detections

Nearly 80% of U.S. households are connected to municipal wastewater collection systems, writes the National Academies in 2023. These sewer systems contain biological waste, including discharged pathogens. Research demonstrates that poliovirus transmission predominantly follows the oral-fecal route. The WHO, the U.K. Health Services Agency, the European CDC., and the U.S. National Institutes of Health (NIH.) say three types of vaccines can prevent polio but may indirectly enable virus shedding. As of 2023, Japan, Australia, and New Zealand conducted poliovirus wastewater testing. On November 30, 2022, the U.S. Centers for Disease Control and Prevention (CDC) announced expanding wastewater testing. In 2022, Dr. José R. Romero, Director of CDC.'s National Center for Immunization and Respiratory Diseases, indicated that poliovirus wastewater testing would continue into 2024. For more information, the CDC Poliovirus Wastewater Surveillance System webpage was updated in July 2023. Separately, WastewaterSCAN, based at Stanford University, is in partnership with Emory University and is committed to transparency, scientific rigor, and open science. 

Poliovirus Detroit, Michigan

The Michigan Department of Health and Human Services announced in July 2023 that it is collaborating with local partners to begin wastewater testing for poliovirus in Oakland County, which has a population of about 1.2 million. On August 23, 2022, Michigan reported that 31% of young children were overdue for routine vaccinations, including polio.

Poliovirus Philadelphia, PA.

The U.S. CDC. announced it would begin collecting wastewater samples from Chester County, Pennsylvania, which has a population of about 500,000, for analysis at the CDC.'s polio laboratory.

Poliovirus New York

The State of New York (N.Y.) reported as of January 15, 2024, sequencing analysis from 3,266 samples confirmed one cVDPV2 positive sample of concern had been found in Rockland County, NY, in March 2023. In 2022, 100 wastewater samples (Sullivan, Rockland, Orange, Nassau, and New York City) were genetically linked to a polio patient (Acute flaccid myelitis) identified in N.Y. The U.S. C.D.C. reported (slide #13) on June 21, 2023, that about 1 to 2 thousand people in New York may have asymptomatic polio infections.

On September 28, 2022, a 'Declaration of an Imminent Threat to Public Health for poliovirus' was issued by Mary T. Bassett, M.D., M.P.H. Commissioner of Health, NY. The New York State Department of Health announced on January 23, 2023, that to enhance local detections, it received $21.6 million to expand its wastewater surveillance and infectious disease monitoring capabilities. As a result, N.Y.'s current wastewater network will expand to over 215 water sheds, reaching about 81% of N.Y.'s population served by public sewer systems.

As of March 2023, the New York Health Department confirmed that under specific situations (HEALTH ADVISORY Update #3), a one-lifetime booster dose of the IPV vaccine should be offered to adults who have previously completed their polio vaccination series and are at the highest risk of infection. In addition, as of March 10, 2023, the New York Department of Health informed New Yorkers planning to visit Israel in 2023 and other countries with circulating poliovirus to confirm their polio immunization status before traveling abroad. The Governor of NY, Kathy Hochul, announced she extended Executive Order 21.1, expanding the vaccination authorities for certain N.Y. health providers on October 9, 2022.

Poliovirus Africa

As of October 2023, there have been 117 confirmed cases of circulating variant polioviruses and 107 detections in sampled wastewater in the African Region in 2023.

Poliovirus Canada

On December 23, 2022, the Canada I.H.R. National Focal Point reported detecting VDPV2 in various wastewater samples collected in August 2022 from a wastewater treatment plant and a target site in Montreal, Quebec. Genetic sequencing confirmed it was linked to the cVDPV2 detected in New York in 2022. Additionally, in January 2023, two cVDPV2-positive environmental samples were collected in Canada. As of January 30, 2023, no confirmed or suspected cases of AFP were investigated in the affected Canadian jurisdiction in 2022 - 2023. Poliovirus type 2 (PV2) isolates were identified in sewage samples collected in Canada in 2022 and 2023.

Poliovirus England

The U.K. Health Security Agency (UKHSA) declared a "national incident" in June 2022 after poliovirus detection in sewage in London, England. Detection of 118 genetically linked poliovirus isolates related to the serotype 2 Sabin vaccine strain collected in 2022, reported The B.M.J. and The Lancet. In addition, environmental samples of vaccine-derived poliovirus type 2 isolates genetically linked to polio cases in New York and Israel were found in north and east London boroughs. 

Poliovirus India

The health department in Pakistan's Sindh province reported about 20 poliovirus samples in Punjab, Khyber Pakhtunkhwa, and Karachi in 2023. India reported the last case of polio in January 2011 but continues to immunize children under five years against polio as part of routine immunization.

Poliovirus Israel

As of March 10, 2023, Israel has been confirmed to have cVDPV2 and cVDPV3 in the wastewater sewage of many localities. In early March 2023, JPost reported the Health Ministry's announcement that an unvaccinated child from the Safed region in Galilee arrived at Ziv Medical Center and tested positive for AFP. On March 2, 2023, the Times of Israel reported the Health Ministry's confirmation that three other children tested positive for poliovirus.

Acute Flaccid Myelitis 

The U.S. National Institutes of Health says poliomyelitis (polio) is a viral disease that can range in severity from self-limiting disease to meningitis. In its most severe form, it may present as acute flaccid paralysis (AFP) and is defined by the acute onset of weakness or paralysis with reduced muscle tone in children. The U.S. NIH. says AFP surveillance is the standard for detecting cases of poliomyelitis in anyone under 15 years of age. The WHO issued the recommended surveillance standard for poliomyelitis, and the Pan American Health Organization (PAHO) published AFP Surveillance Data segmented by Country for 2022.

Polio Vaccines

According to the U.S. C.D.C., polio is a vaccine-preventable disease. For the latest polio vaccine information, visit this Precision Vax webpage.