This is a summary, written by members of the CITF Secretariat, of:

Kandola K. Age-stratified SARS-CoV-2 Serological Prevalence Estimation Using Anonymized Residual Sera Following Delta and Omicron Waves in the Northwest Territories (NWT). Unpublished results. 2023 Nov 22.

The results and/or conclusions contained in the research do not necessarily reflect the views of all CITF members.

A CITF-funded study, conducted among residents in the Northwest Territories (NWT), found that seroprevalence due to vaccination or infection was greater than 95% in all age groups throughout 2022. Seroprevalence due to infection rose substantially between March 2022 and January 2023. These are unpublished results. This study was led by Dr. Kami Kandola (Chief Medical Health Officer, Government of Northwest Territories) in collaboration with Dr. Sarah Jeffrey (Territorial Epidemiologist, Government of Northwest Territories).

Key findings:

  • Seroprevalence due to infection rose in all age groups in the NWT from March and May 2022 (47.3%) to January 2023 (79.5%).
  • Children and young adults (under 25 years old) experienced a rise in infection-acquired seroprevalence earlier in 2022 than did older adults. Due to the smaller sample size in children (especially children under 12 years old) and young adults, the trend over time was less clear.
  • Adults over 60 years old maintained a lower infection rate throughout 2022, a similar phenomenon to the one seen in Canadian blood donors.

This study involved 2,999 participants recruited in the Northwest Territories with sampling periods of March and May 2022, October 2022, and January 2023 for SARS-CoV-2 anti-nucleocapsid antibodies. The mean age of participants was 49 years old and 95% of participants fell within an age range of 12 to 83 years old. See the results in graph form on our Seroprevalence in Canada page.