There's barely any uptake in Canada. Not that it matters, the only way you'd get a one-time key to trigger alerts for others is through a PCR test, which public health, as of this moment, will not do PCR test for symptomatic people unless they're in a high risk group.

Went and donate blood mid Dec 2021, it's one of the things that I kept up, because people still need that stuff. 10 days later, I get a email from them saying that I may have been exposed. While it's nice that they notify me, it's not from public health's contact tracing.

We've tried nothing and it doesn't work.