Thread by @PennyDaflos

COVID variants are a major concern for health officials right now -- not to mention the rest of us.
I'm seeing a lot of ?s about how BC is testing for them so here's a thread w FAQs and info directly from a @CDCofBC environmental microbiologist who spoke with @CTVVancouver . 1/x

First, if you want a quick 2 minute rundown in video format about how many variants we have in BC, what's going on, and the testing info, watch this: bc.ctvnews.ca/b-c-up-to-28-i… 2/x

We spoke with Natalie Prystajecky, the program head for the environmental microbiology program at the BCCDC public health lab. She had a really great way of explaining what's they do.
A HUGE point to know: only a handful of labs in the country can test for COVID varriants. 3/x

BC has only one lab that can do that work.
Why? Variants happen with mutations within the COVID virus, so rather than a "yes/no" test to see if someone has COVID, the variant test has to check the ENTIRE virus to see if it has the variants that make it more contagious. 4/x

Sounds time-consuming? It is! It can take 4-7 days to sequence the ENTIRE genome of the virus, which is why they can't do a lot of tests. Last week they only ran through 900 tests. The number of variants found in BC doubled over the course of a week: bc.ctvnews.ca/b-c-up-to-28-i… 5/x

They obviously need to test more but how do you do that when it takes so long and you need special equipment? You try to search only the section you need to. Prystajecky compared it to looking for a few sentences in a book, rather than reading the whole thing. 6/x

What that means, though, is they're testing for 3 variants that all have the same mutation (sentence) in their genetic sequence (book). Once they get a hit, then they see if it's the B117 (UK), B1351 (South Africa), or P1 (Brazil) variant. 7/x

It's really smart the way they do it, because it's funnelling to become more and more specific.
1. Test for COVID
2. Positive tests only sent for quantitative PCR test
3. Positive PCR test THEN gets sent for full genetic sequencing 8/x

This way, they hope that with expanding lab capacity, they can test for hundreds of variants per day, rather than per week.
Side note, micriobios are adorable: the spike protein mutation (variant fingerprint) they're looking for is N501-Y.
They've nicknamed it Nelly. 9/x

This is a simplified summary and I'm sure I'm missing a lot of details and interesting stuff but I wanted to explain why we can't test everyone for variants all the time. RNA viruses include a "constellation of mutations" so this is what they're searching for now. 10/x

I want to end with the most important and sobering part of our interview: they're not just screening for known variants.
They're searching intently for possible home-grown variants as well, whether it's here in BC Or elsewhere in Canada. 11/x

So they're doing whole genome sequencing to make sure we're not watching for one thing and missing sthg new.
This is intense, painstaking work and we owe a debt of gratitude to the people doing the microscopic detective work to watch for the next risk to our communities. 12/12