Ok. Educational thread. #COVID19 #vaccine #strains #Mutation

First a caveat. Until we have good data most of this thread is theoretical, but to keep you out of suspense, I believe that our current vaccines will protect us from evolving strains of coronavirus.
The reason for this is that the target chosen for these vaccines was its virulence factor, the thing that makes this normally annoying old virus deadly. The capsid spike protein that interacts with our bodies ACE2 receptor.
Viruses need a way to get into cells to infect them. Previous generations had spike proteins that opened doors on tissues of the throat and nose. The ensuing infection and inflammation is the stuffiness that we associate with a cold. You can survive a sore throat.
Viruses may not be smart, but they are fast and plentiful, and random mutations during billions of replication modified this key along the way. Most of these new keys would not turn in the cellar locks. These viruses failed to reproduce and disappeared along with their keys.
Some keys were improvements, fitting better into existing locks and opening the doors easier. Anyone who has had a poorly cut key knows how much jiggling and futzing it can take to turn a lock cylinder. These were more efficient and hence more infectious viruses.
Eventually a key was found not to just the throat, but to every part of the body, via blood vessels. This was pivotal. Now more cells to make more virus. That’s an evolutionary advantage... for the virus, but only if it doesn’t kill off its host.
These new variants, to remain problematic must maintain similarity to the original spike protein. It doesn’t have to be perfect but it has to be very close. Too different and the key no longer fits the lock. When that happens, the virus is relegated to its old ways. The throat.
We’ve seen this new variant B1.1.7 refine its key to better fit our locks, but it still fits the antibodies created by these vaccines well, and hence will be managed by the vaccine.
Any other modification to spike proteins that are drastic enough to not fit antibodies should also not fit the ACE2 receptor.
Now there is nuance to this. Just as receptor affinity influences infectivity, it will likely influence vaccine protection, and so these variants may reduce effectiveness of the vaccines, but this remains to be seen.
Overall, however the best thing we can do is continue with rapid vaccination to reduce population morbidity. In effect providing evolutionary pressure to push the virus back to its old ways, while allowing it to naturally attenuate.
Cuz in the end Rona doesn’t really want to kill us. That was just an unfortunate side effect. 🤔
Also full apology to virologists, immunologists and microbiologists, as my courses were taken years ago. And also my eternal gratitude. Please correct me ad lib!

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More from @drdagly

27 Nov 20
A short tread on community.
You might know that I am a champion of @coffee_outside. It was a simple idea that brought people together every Friday morning in a local park. Most arrived by bicycles and some even drank tea but that wasn’t it was all about.
It was really about being connected with people who were once strangers. It helped that we were like minded souls, but given time and commitment it flourished just as those relationships did.
Like other things in this crazy time, it has dwindled. Despite being outside by nature our group has gotten smaller. Like a seed that drys.
Read 6 tweets
13 Nov 20
So this really struck a chord with people. Let’s dive in.
This is not where we are now, but given the ICU admission rates and EXPONENTIAL growth rate of cases, coupled with our inability to contact trace in a timely matter, this is where we are heading. Unless something is done.
If you are reading this thread, you are probably mostly in agreement with the problem. The challenge is to depoliticize this issue. We were all together on this in March, and as a result the first wave was brought under control. Our eastern provinces still have control.
Read 18 tweets
7 Nov 20
Some uncomfortable truths about ageism and #COVIDー19. The average life expectancy of someone who lives to 80 is 9 years, they however are most likely to die if infected, and should they get sick enough to need ICU support their mortality pushes 80%
Consequently, they rarely are admitted to ICU. This means:
1. ICU occupancy lags hospital admission rates significantly and is an insensitive metric for healthcare capacity and strain.
2. These are preventable deaths that take significant number of quality years with them.
The bad news is that it is a statistical game. As hospital numbers increase, so will the proportion of people with favourable ICU outcomes who need our care. That’s when we start filling our beds. When those people get sick they take weeks of treatment.
Read 5 tweets
19 Aug 20
I apologize to everyone I could not individually reply to. So a brief thread about ICU capacity, as it pertains to Edmonton in the time of #COVID19.
Edmonton’s General ICU beds are spread out amongst all of its hospitals. We have two major trauma centres situated at the University Hospital and Royal Alexandra Hospital. The Sturgeon, Grey Nuns and Misericordia handle both surgical and medical disease.
The university also has the Mazinkowski which manages heart surgery and ECMO, and a neurosurgical ICU. The RAH has multiple step down units, both surgical and medical that can act provide high level care.
Read 13 tweets
24 Jul 20
So here I go into turbulent waters. I do so because I have had several requests to weigh in on the matter of #Masks. I would like to qualify my statements first. I am not an infectious disease specialist. I would refer you to @AntibioticDoc for a higher level of expertise.
I do believe that non medical masks play an integral part in the mitigation and management of the spread of #COVID19. I use the word believe specifically because despite the recent proliferation of studies around masking, they are mostly of poor quality and applicability.
If you follow me you know that I despise oversimplifications. My concerns about masks from the very beginning has been the need to portray it as a solution to the pandemic, as way to get kids back in school, and people back to work. In a sense, a magic bullet.
Read 13 tweets
11 Apr 20
Allow me a brief thread that will first cause you some anxiety but then reassure you. I will preface this with my credentials. I have been an intensive care physician for 15 years now. Long enough have gained a fair amount of experience in these matters.
It is inherent in our nature to look for answers. It is also natural for us to seek the easiest way to accomplish a task. I’m not an evolutionary biologist but it makes sense to me to expend the least amount of effort to survive.
We have a tendency to seek simple solutions to complex problems. A perfect example: vitamins. A multi billion 💵 industry based on only the scantest of evidence. In some clinical circumstances they are beneficial, sometimes life saving but in most cases the make expensive pee.
Read 15 tweets

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