How rapid COVID-19 test kits will help keep N.S. children safe

Nova Scotia families with children in pre-primary to Grade 6 have started receiving free rapid COVID-19 test kits.

Children under the age of 12 can't be vaccinated against COVID-19, so the province has implemented a pilot project aimed at protecting youth through testing.

Dr. Peter Lin, a family physician and CBC medical columnist, spoke with CBC Radio's Information Morning Halifax on Thursday to explain how the tests work and how they will keep young children safe during the pandemic.

This interview has been edited for length and clarity.

Tell us a bit more about the rapid tests that are being given out in schools here in Nova Scotia. How do they work?

You take the swab from your nose and then you swirl it in a test tube of chemicals, and then you take that liquid and you put it on something that looks like a pregnancy test strip and then you wait 15 minutes. 

If the line shows up, then that means you're positive for the virus. This test is only looking for stuff on the outside — that spike protein business on the outside of the virus. It's not trying to get the blueprints or anything like that, so that's why it's very simple to do. 

Basically, what the [scientists] did was they took antibodies that can recognize the spike protein and they put it on this strip of paper. If there is a spike protein in that liquid sample, then the antibodies will grab it and then this new complex will change colour.

How accurate are the rapid tests?

This is the part where it depends on how much virus is on the swab. If you have lots of virus on that swab, the antibodies will be able to grab it and lots of colours will change. The tests are over 90 per cent accurate. 

However, let's say you have a few viruses on the sample. Well, they will be grabbed and there will be a colour change, but not enough that you can see because there's not enough particles there, so you'll be reported as being a negative even though there's still virus sitting there. We're going to miss a few people this way. 

The tests themselves are quite cheap and so therefore we can do it more often and it's easy to do. If I did it today and then I did it two days from now or three days from now, then I have a chance to pick it up, so the accuracy of the test improves as we do more tests.

Who should be getting these rapid tests?

Right now in Canada, rapid tests are being used for people with no symptoms. 

In other countries, they're saying if you have symptoms, go do the rapid test. If you're positive, then you isolate — you don't go to work, you don't go to school. That way, you don't bring the virus to the other people, so you end up protecting the herd. 

For this to work, people need to have a few test kits at home so that they can do the testing at home. It doesn't make sense to have tests all at school or at work. It makes sense for them to have it at home. 

Right now, kids have a lot of coughs and colds — school has started. Officially, they have [COVID-19] symptoms, so according to the rules, they have to go line up for a PCR test and wait two days for the results. 

I think most parents would rather do the test at home. Fifteen minutes later, they know what to do. If they're positive, they need to isolate from school, and more importantly, they need to isolate from the rest of the family. So that way, we don't spread the virus within the family. 

What does a good testing strategy look like? 

We're going to have limited supplies of these [rapid tests] so … a better way to do it, is to say, 'In this area, there's zero COVID-19, therefore you don't need testing. In this area, there is COVID-19, so we need to test there.' Twice-a-week testing is a good thing for kids. 

If you have a bunch of weeks with no positive tests, then maybe that family's routine is very low risk and if you're not testing positive, you're not likely to expose [others], so maybe we can drop off testing in the future. 

But if you change your exposure risk, like let's say you decide to go to the United States and there's no masks down there. Now, if we come back, we need to test because we changed our exposure.

So let's use everything in our power to protect our unvaccinated kids. Let's use the masks. Let's use distance, ventilation, vaccines, and now testing. Let's just do everything ... so that way, our kids are not saddled with this virus for the rest of their lives.