The BC Centre for Excellence in HIV/AIDS (BC-CfE) and Simon Fraser University conducted research in response to reports in Saskatchewan of unusually rapid progression of HIV to AIDS-defining illnesses in the absence of treatment—revealing genetic mutations in HIV strains in that province.

The study, presented at the 2018 AIDS Conference in Amsterdam and published in the scientific journal AIDS, shows that HIV strains circulating in Saskatchewan have adapted to evade host immune responses. These HIV strains are being commonly transmitted and, if the resulting HIV infections are left untreated, rapid progress to AIDS-related illnesses may happen.

Researchers on the study—from the BC-CfE, SFU, and the Public Health Agency of Canada, in partnership with Saskatchewan physician-researchers and with funding from the Canadian Institutes of Health Research—were startled at the prevalence of immune resistance mutations. One key mutation was found in more than 80% of Saskatchewan HIV strains, compared with only about 25% of HIV strains found elsewhere in North America. The pervasiveness of such mutations is increasing over time. More than 98% of the HIV sequences collected in Saskatchewan most recently (2015 and 2016) harbored at least one major immune resistance mutation. HIV antiretroviral treatment, however, works equally effectively against immune-resistant HIV strains.

The multi-year analysis compared more than 2300 anonymized HIV sequences from Saskatchewan with data sets from sites across the United States and Canada. Genetic analyses of HIV strains in Saskatchewan showed high levels of clustering—indicating that viruses with similar mutations are being frequently and widely transmitted.

This study is significant as HIV incidence rates in Saskatchewan are among the highest in North America, with 2016 rates in some regions more than 10 times the national average. Saskatchewan’s HIV epidemic is also unique in that nearly 80% of infected persons self-identify as having Indigenous ancestry.