Poliovirus Detected in Canadian Wastewater

The Pan American Health Organization / World Health Organization (PAHO/WHO) recently confirmed that Canada joined the United States, Israel, and the United Kingdom in detecting vaccine-derived poliovirus type 2 (VDPV2) in wastewater samples in 2022.

The Canadian National Microbiology Laboratory (NML) retrospectively tested wastewater samples and found 3 of 26 samples tested positive for poliovirus by real-time PCR.

The NML stated it would test archived wastewater samples at relevant treatment plants collected between September and December 2022 and until the end of February 2023 for poliovirus.

The PAHO/WHO disclosed on December 23, 2022, the Canadian wastewater samples that tested positive for VDPV2 were collected in August in areas with close connections to New York communities, where similar wastewater-positive samples were found from April to December 2022.

Poliovirus is detectable when people shed the virus in wastewater.

Most importantly, the PAHO/WHO stated there had been no confirmed or suspected cases of acute flaccid paralysis (AFP) patients investigated in the affected jurisdiction in 2022.

In the U.S., the Centers for Disease Control and Prevention (CDC) announced on November 30, 2022, Dr. José R. Romero, Director of CDC's National Center for Immunization and Respiratory Diseases, would lead poliovirus testing outside of New York.

By the end of 2022, New York had confirmed over 90 positive wastewater samples detected in various counties.

The Michigan Department of Health and Human Services and the Philadelphia Department of Public Health are among the first locations to explore plans to collect poliovirus wastewater samples. 

In November 2022, the WHO agreed that the risk of the international spread of poliovirus remained a Public Health Emergency of International Concern and extended its notice into 2023.

As of January 4, 2023, the Global Polio Eradication Initiative confirmed polio cases continue to be reported worldwide.

New polioviruses reported this week included:

• Afghanistan: three WPV1-positive environmental samples
• Algeria: one cVDPV2 case
• Central African Rep: one cVDPV2 case and one CVDPV2 positive environmental sample
• DR Congo: two cVDPV1 cases, 11 cVDPV2 cases and two cVDPV2 positive environmental samples
• Madagascar: 11 cVDPV1 positive environmental samples

The CDC says polio is a vaccine-preventable disease. 

Most people who get infected with poliovirus will not have any visible symptoms. However, about 25% with poliovirus infection will have flu-like symptoms.

A smaller proportion of people with poliovirus infection will develop other, more severe symptoms that affect the brain and spinal cord.

Paralysis is the most severe symptom associated with poliovirus because it can lead to permanent disability and death, says the CDC.

In the U.S., the IVP vaccine has been available at most clinics and pharmacies since 2000.

Other countries offer versions of the oral polio vaccine.

Additional polio outbreak 2023 news is posted at PrecisionVaccinations.com/Polio.

Disclosures: Data sources included the WHO, PAHO, CDC, and New York Health. Headline updated on Jan/ 10, 2023.