🧵on the Toronto area SGTF (S-Gene Target Failure) study to detect B117 (UK variant). It looked at 11,485 positive tests over Dec 16 to Feb 3 and found 448 had SGTF* (3.9%). These charts show the growth.
https://t.co/5L8tF0MwDv

2. Note: Not every SGTF is B117 but almost all were confirmed with WGS (whole genomic sequencing). Rt for the SGTF was 1.17, non-SGTF were .82 meaning SGTF had an Rt 44% higher. This means that B117 is growing quickly (80% per week in recent weeks) and is projected to overtake

3. the old variants around Feb 20th in the Toronto area. Because the Rt (reproduction number) was only .82 without B117, we know the lockdown was working well in Toronto. It's only because the variant was a small share that infections and cases fell. If it had reached 100%,

4. then every infection would have infected 1.17 more infections and we would have had exponential growth EVEN IN LOCKDOWN where we have seen cases plummet.

5. This data is for the Toronto area. The projections have uncertainty - Feb 20 is approximate but once B117 becomes increasingly dominant over the next 6 weeks, current lockdown efforts would be hard-pressed to stop R from moving above 1, meaning an exponential growth in cases.