The major rapid test that's available on the Canadian market right now is the Panbio by Abbott. This is a lateral flow assay. It looks very much like a pregnancy test. People get a nasopharyngeal swab. From what I understand, Health Canada is looking at approving nasal swabs to make it a little more tolerable. It's put into a tube; the tube is dropped onto a pregnancy test, basically, and you wait 15 to 20 minutes for a result.
Sensitivity—and again, this is approval, as compared to PCR—in people who are symptomatic is about 75% and specificity 95%. That being said, the sensitivity improves in people who have very high levels of circulating virus. One of the things that got discovered in the McMaster study...as we know, PCR tests tend to stay positive in some individuals for some time. It's not a reflection of their infectivity. It's a reflection of shedding virus.
That is a double-edged sword, in that sense, whereby if you PCR everyone who comes back, you may have a wait time, and you may get data that might not actually be usable. Dr. Smieja, who was part of that study, really did pick up a lot of people with what we call high-cycle thresholds of very low levels of virus. These rapid tests may pick up the people who are more clinically relevant, the people who are actually infectious and a threat to people, rather than picking up the people at the very early ends of their disease and at the very non-infectious late ends of their disease.
We are looking at these tests in long-term care and we're looking at these tests for surveillance for other populations, recognizing that in someone who's symptomatic, I don't want to give them this test necessarily on its own. But if it's someone who's asymptomatic and who's feeling fine and I get a positive, I'm treating that person as if they're positive, because they're probably asymptomatic, infectious and walking around.
It's a double-edged sword. I think these tests, as Dr. Bogoch mentioned, actually do have a role in this type of testing just for rollout, for lowering laboratory requirements. Again, if you use them serially, they're effective, too, as long as they're done properly. Plus, again, the training can be done outside of a laboratory, not in the laboratory.