COVID-19 and the delta variant didn’t deter more than 33,000 Saskatchewan Roughriders fans from packing Mosaic Stadium in Regina on Aug. 6 for a game against the B.C. Lions. Public health measures remain lifted while cases are spiking in the province. (Kayle Neis/The Canadian Press)

Canada’s western provinces are largely driving the country’s fourth wave of COVID-19 cases, and physicians are now raising the alarm — saying lax and late public health measures helped spark a rise in serious infections that’s already putting pressure on hospitals and impacting patient care.

In British Columbia, Alberta and Saskatchewan, infection rates are high above the country’s average and far beyond every province to the east, including Ontario, whose population is larger than all three westernmost provinces combined.

The rate of cases in the last seven days in B.C. was 93 per 100,000 people as of Aug. 30, federal data shows, with Alberta’s rate at 159 and Saskatchewan’s at 135 — with no province to the east hitting more than 43.

In terms of raw case growth, Alberta currently has the most new infections in the country, with more than 7,000 cases reported in one week.

The province is now in the early stages of postponing surgeries and transferring patients to help boost capacity, but it has yet to reinstate major public health measures or bring in a vaccine mandate to curb case growth as the fast-spreading delta variant surges across much of the country.

Read more from CBC Health’s Lauren Pelley on the surge in COVID-19 cases in Canada’s western provinces