UPDATE - Yellowknife Cluster and Wastewater Signal Investigation

News Type: 
Public Service Announcement

YELLOWKNIFE - APRIL 28, 2021 – The NWT Office of the Chief Public Health Officer (OCPHO) has confirmation of that some COVID-19 cases in Yellowknife are caused by the variant of concern (VOC), B.1.1.7., also known as the U.K. variant.

The positive COVID-19 wastewater signal from Yellowknife that was announced on April 19 was confirmed for B.1.1.7. The OCPHO collaborates with both Taiga Lab in Yellowknife and the Public Health Agency of Canada’s National Microbiology Laboratory (NML) for wastewater testing. The NML confirmed this result.

Individual cases are confirmed by Alberta Precision Labs. All five individuals who are part of the cluster picked up by wastewater testing are confirmed with COVID-19 caused by B.1.1.7., reflecting the wastewater findings.

There are six confirmed COVID-19 cases in Yellowknife. Five are a part of the cluster. The other is not related.

More than 900 tests have been performed since the advisory was announced on April 19, 2021.

Variants of Concern

Variants of concern now make up the majority of positive COVID-19 test results in many parts of Canada. Therefore, the NWT OCPHO is treating all new infections in the territory as VOCs until confirmed otherwise. The GNWT routinely monitors for variants of concern through laboratory studies.

VOC Screening

  • Samples from people that are positive for SARS-CoV-2, which is the virus that causes COVID-19, are sent to the NWT’s southern lab partners where scientists screen the specimens for any VOCs (Alberta Precision Labs).
  • After VOC screening, which determines that the specimen is a VOC, lab partners attempt “whole genome sequencing” which reads the entire genetic code of the virus.
  • Sequencing is always attempted however it is not always possible to confirm results.
  • Currently there are delays in getting back VOC results. Alberta Precision Labs is screening all Alberta specimens for VOCs as well.

Wastewater surveillance

Wastewater surveillance is ongoing in order to monitor whether the signal is increasing or decreasing. At present, the level has been holding steady.

Continue public health measures

Public health guidance in Yellowknife and the NWT remains the same:

  • Anyone with symptoms of COVID-19, especially household members of someone who was/is isolating in Yellowknife, should arrange testing for COVID-19 and follow isolation guidance.
  • Follow self-isolation guidance as required.
  • Stay home if you are sick.
  • Wear a non-medical mask in public places.
  • Wash hands frequently
  • Physically distance at 2 metres when possible
  • Practice healthy respiratory hygiene

Public risk

There is no public health risk associated with this update.


All commentary is attributable to Dr. Kami Kandola, Chief Public Health Officer for the Northwest Territories.

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