Attachments
On 23 December 2022, the Canada IHR National Focal Point reported a detection of a vaccine derived polio virus type 2 (VDPV2) in two wastewater samples collected in August 2022 from Canada. The United States’ CDC is examining the positive wastewater sample sequence data to assess any genetic linkages to VDPV2 samples collected from New York State. In light of this, the Pan American Health Organization/World Health Organization (PAHO/WHO) reiterates to Member States the need to have an updated response plan for polio outbreaks or events, join efforts to achieve vaccination coverage against poliomyelitis >95%, strengthen and maintain epidemiological surveillance of acute flaccid paralysis for the rapid detection of cases.
Situation summary
Canada
On 23 December 2022, the Canada IHR National Focal Point reported a detection of a vaccine derived polio virus type 2 (VDPV2) in two wastewater samples collected in August 2022 from Canada. According to the report, the specimens were collected between 20 and 30 August 2022, from a wastewater treatment plant and targeted sites in the affected area after the report of the case of VDPV2 in New York State. The target sampling sites were determined based on close connections with communities in New York and the surrounding areas where VDPV2 was detected.
The Canadian National Microbiology Laboratory (NML), retrospectively tested wastewater samples and found that 3 of 26 samples tested positive for polio by real-time PCR. On 23 December 2022, two of the three samples were confirmed to be VDPV2. The environmental sample collected on 27 August, from a large wastewater treatment plant, is VDPV2, with 8 nucleotide differences from the Sabin 2 VP1. The environmental sample collected on 30 August, from a targeted site, is a VDPV2, with 6 nucleotide differences from the Sabin 2 VP1. The environmental sample collected on 20 August is pending confirmation by virus isolation.
All other samples (n=23) tested negative for poliovirus detection, including samples collected from targeted sites and wastewater treatment plant of the affected area between 31 October and 9 November 2022 (n=12). The NML will test archived samples collected between September and December from wastewater treatment plant in the affected area for poliovirus.
The United States’ CDC is examining the positive wastewater sample sequence data to assess any genetic linkages to VDPV2 samples collected from New York State. The NML and the affected jurisdiction plan to continue sampling the wastewater sites (one collection per month) until the end of February 2023.
There have been no confirmed or suspected cases of acute flaccid paralysis (AFP) being investigated in the affected jurisdiction in 2022.
PAHO/WHO is working together with the Public Health Agency of Canada to follow up on this event.
United States of America
In the United States of America, since the September 2022 detection of VDPV2 in in New York State, the US-CDC confirmed the presence of 94 positive samples, of which 87 are genetically linked to the Rockland County polio case. Of the 87 samples, 44 were collected in Rockland County, 28 in Orange County, 13 in Sullivan County, 1 in Nassau, and 1 in New York City from Brooklyn and a small part of Queens County. Sequencing analysis of the remaining 7 samples (6 collected in New York City and 1 in Orange County) were characterized as vaccinederived poliovirus or Sabin poliovirus variants type 2. All samples were collected between April and October 2022.