"Hi Alex. What is this Western Canadian variant? Is it something to be worried about?"

Yes, there's a new Canadian AY.25 clade which originated from Idaho. This AY sublineage appears to have become dominant in Alberta and Saskatchewan. (1/9)

This is a bit technical, but as you can see in the phylogenetic analysis below, the strain appears to have originated from Idaho and then spread quickly throughout all of Western Canada. (2/9)

The same phylogenetic analysis is now color coded by province, so you can see how the strain has spread widely through BC (sea green), Alberta (yellow), and Saskatchewan (lime green). There's smatterings of cases in Ontario, too. (3/9)

Overall Canadian modeling of AY.25 would suggest that it has roughly a 5% selective advantage over the original B.1.617.2 Delta strain, which would explain why it has taken over in Saskatchewan quite quickly. (4/9)

There is NO evidence to date that this AY.25 clade is more virulent (i.e. causes more severe disease) than the original B.1.617.2 strain that circulated through the summer months and into the fall. (5/9)

Because of the features and prevalence of this Delta sublineage throughout Canada, a designation has been formally requested for this particular AY.25 clade (AY.25.1). (6/9)

While it's easy to assume that larger amounts of community transmission in Western Canada led to emergence of this sublineage, it's not that simple or that easily correlated. Viruses mutate, unfortunately. (7/9)

CAVEAT: I am just a dumb clinician, NOT a virologist.

I'd invite any number of esteemed colleagues here in the Prairies (i.e. @angie_rasmussen @akelvinlab @KindrachukJason) to provide their insights & perspectives on this emergent AY.25.1 lineage. (8/9)

FYI. For reference, the entire SHA Town Hall deck from which these slides were taken are available publicly online at the following link. (9/9)



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More from @awong37

7 Nov
"Hi Alex. My 11 year-old is ready to get vaccinated. BUT, he/she turns 12 in less than a month. Should I wait and get the higher 30 μg dose of vaccine at age 12, or just go ahead & give the lower 10 μg dose right away?"

Answer: DON'T wait, go right away.

🧵 below. (1/7)
The appropriate dosing of vaccine ISN'T dependent on weight, but rather their age. The immune system of a 'small' 11 year-old is functionally the same as a 'large' 11 year-old. The immune response isn't weight-dependent, per se. (2/7)
Younger children in general have very active immune systems, another reason why lower dosing makes sense and leads them to produce the same degree of antibody response as those ages 16-25 who received a higher dose of vaccine. (3/7)
Read 7 tweets
27 Oct
"Hi Alex. If vaccinated folks can transmit #COVID19 like unvaccinated folks, why get vaccinated? Negative testing is good enough!"

Fully vaxxed persons transmit #COVID19 at FAR LOWER LEVELS than unvaxxed persons. Rapid antigen testing has limitations.

🧵 below to explain

If you're fully vaccinated, your chances of getting #COVID19 infection are MUCH lower, so your chances of transmitting are ALSO much lower too.

If you're fully vaccinated but still get #COVID19, you clear the virus MORE quickly, so you're less contagious overall.

This is why being fully vaccinated & PREVENTING #COVID19 infection is BETTER than just doing negative lateral flow testing (LFT, "rapid" tests).

Persons who are fully vaccinated protect themselves from infection as well as those around them MUCH BETTER.

Read 7 tweets
27 Oct
"Hi Alex. Do #COVID19 vaccines affect fertility? Should I get it if I'm pregnant?"

There's SO MUCH misinformation about how COVID-19 vaccines aren't safe in pregnancy or can affect fertility. THIS IS NOT TRUE.

Excellent link 👇 & short 🧵.


All the information we have with billions of doses of #COVID19 vaccine given is that there's NO EVIDENCE that COVID-19 vaccines affect fertility at all.

Every person, whether actively trying to conceive or just thinking about conceiving, SHOULD be vaccinated.

Acquiring #COVID19 while pregnant means a woman is at HIGHER RISK of needing hospitalization & ICU care versus not being pregnant. Being very sick with #COVID19 could be dangerous for baby.

All pregnant woman SHOULD be vaccinated to prevent serious illness from #COVID19.

Read 4 tweets
27 Oct
The benefits of vaccinating ALL children b/w ages 5-11 with Pfizer #COVID19 vaccine OUTWEIGHS known or potential risks.

A long-ish 🧵 on data & risk/benefits thus far.

As an ID physician, I'll vaccinate my 5 year-old w/ confidence, and recommend to others to do the same.

#COVID19 is a serious infection for all kids.

Although kids who acquire COVID are at much lower risk of death than adults, other complications can occur after recovery from acute infection, including Multisystem Inflammatory Syndrome (MIS-C), and Long #COVID.

Much higher rates of infection, hospitalizations, and deaths have been reported in children in last several months in the USA & Canada as a result of widespread transmission of the more contagious Delta variant.

Read 15 tweets
24 Oct
A LONG explanatory 🧵 on ICU 'capacity' & 'flow' in Saskatchewan & why we need MULTIPLE interventions to avoid compromised care for ALL #SK citizens & triage.

I'm going to use an analogy of ICU capacity = bathtub. Patients = water. Health care system = house.

Water is running into the bathtub. That's all the patients who need ICU care in Saskatchewan. Some have COVID, some don't. The patients have now overflowed our ICUs.

To cope, we've built walls up on our bathtub to hold more water. That's our 'surge' capacity.

We can only build walls up on the tub so much, because there's limits on what can be done safely w/ availability of specialized staff, especially nursing & respiratory therapists (who support ventilated persons).

We've reached that limit w/ ~120 pts in #SK ICUs.

Read 19 tweets
22 Oct
Summary 🧵 of last night's SHA "town hall" for MDs:

- Overall #SK test positivity ~14%
- Cases declining, but so is testing
- #SK has HIGHEST current case & death rates of all provinces
- HIGHEST ICU census per capita of ANY province at ANY point in pandemic.

Vaccine & mask mandates have helped, but not enough. #SK remains in exponential growth & cases NOT coming down at this point.

Public health experts @SaskHealth recommend gathering restrictions, including limits on household gatherings, capacity limits, etc.

As of 0730hrs yesterday AM (Oct 21), 117 persons in ICU. 57 persons on high-flow oxygen (Optiflow) normally in ICU, cared for on regular hospital wards.

ICU census now forcing out-of-province transfers, widespread service slowdowns, and informal triage.

Read 8 tweets

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