Meet the N.S. researcher tracking the delta variant and its offshoots

During the pandemic, Nova Scotia researcher Bronwyn MacInnis has been closely watching the evolution of the virus that causes COVID-19, tracking how it mutates into different variants. 

MacInnis is the director of pathogen genomic surveillance at the Broad Institute of MIT and Harvard and she spoke with CBC Radio Information Morning host Portia Clark about her work — and the evolution of the delta variant — on Wednesday.

Their conversation has been edited for clarity and length.

You're specifically looking at genomics surveillance of those variants — what does that mean? 

So I'm tracking variants in New England area, and I'm also thinking about what could be close to home in Nova Scotia and New Brunswick, just across the border. We use the genetic code of the virus by looking at discarded diagnostic materials from positive tests, and we move those into our genomic sequencing pipeline to look at signs of evolution of the virus and the emergence of important variants like delta. 

So what are you seeing in terms of the evolution of variants, specifically the delta variant? 

What we're seeing is that delta is really the story of the moment; virtually every infection in the U.S. and Canada, and around the world, right now is delta. But if you look deeper at the family tree of delta, it's starting to grow offshoots that we're tracking closely to see what these sons and daughters of the delta variant look like, and what they might mean for any new features of how this virus spreads or causes disease. 

Do those offshoots look different than the original delta variant? 

It's early days so it's a little hard to say for sure, but we're starting to see some differences; sometimes they look even slightly more transmissible, although it's definitely too soon to know how much of an impact that will have. Often new variants will die out before they really cause much trouble, so I think we're just in that phase right now where we don't know whether this will continue to be a problem, could possibly get worse or actually start to fizzle. 

How soon might we know whether these sub-branches of the delta variant can transmit more quickly? 

I think these variants of concern really caught us by surprise back in the winter and spring, but in the time since then there's been just tremendous efforts globally to be doing this more quickly, more comprehensively and to really get ahead of these variants. Now we're detecting them at the earliest possible stage — before they've kind of exploded and become a problem — and then hopefully we can use that information to target strategies to control their spread. 

What might those strategies look like if these offshoots are somewhat unknown? 

It's still the same kind of tool kit: increasing vaccination campaigns, returning to masking in indoor places in some regions that have kind of loosened those restrictions, or possibly introducing or reintroducing gathering limits — the standard public health tools that really are effective in controlling spread. 

If those who are vaccinated are exposed to the virus, can the virus still replicate and mutate and then spread to another person? 

The answer to that question is yes. But if you're fully vaccinated, the chance of getting infected in the first place and then causing an infection, causing disease and then onward spread, is just much, much lower. So vaccination is not a complete firewall against infection and replication and spread, but it really blunts the ability of the virus to do that. It is the best weapon in our arsenal. 

So far, the vaccines seem to be holding up against the common delta variant. Could we see a mutation where the vaccines are not effective? 

I think that is the worst-case scenario and something that we are all trying to mitigate against and prevent. It's theoretically possible, but with high and continuing-to-grow vaccination rates — and all the work that we're doing to blunt transmission — we hope that that won't be the case. 

But that's really the race. It's how quickly can we get folks vaccinated and how can we get even beyond 75 per cent target of people vaccinated. With delta, we think we need numbers closer to 90 or even 95 per cent vaccination to kind of win the arms race against the virus.

And the more people who are vaccinated, the better chance we have of winning that.

MORE TOP STORIES