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This is a mistake and one that is made by many people who don’t understand vaccine efficacy rates.
Steve says that an 80% efficacy rate against breakthrough infection means that 20% of vaccinated people will get covid. And he says that means that we can expect 10k of SFU’s 50k community to get infected.
This is wrong. The efficacy rate of a vaccine indicates how significantly one’s risk is reduced compared to an unvaccinated person. So, if an unvaccinated person has, say, a 1/10 chance of contracting a contagion, then someone who takes an 80%
effective vaccine would have their chance of contracting the contagion reduced by 80%. In this scenario, that person would have a 2/100 probability of contracting the contagion.
If the attack rate of covid were 100% - i.e., if it were true that covid was so infectious that every unvaccinated person could be expected to get it in an acute outbreak - then Steve’s point would be true. We could expect 20% of people protected
by an 80% effective vaccine to get covid. But the attack rate of covid is nowhere near 100%. So
far fewer than 20% of vaccinated people will get covid (at least in the current outbreak). That means that Steve’s 10k number is dramatically inflated.
I’m not suggesting that Steve’s other points - about unvaccinated children and the risk to the community - are incorrect. And I’m not suggesting that we free ourselves from all restrictions. We are obviously in the midst of a very serious outbreak
and should mitigate our risk appropriately.
But the conversation that we are having is not helped by this kind of misunderstanding of the basic math of epidemiology.
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Dr. Dai Heide
Senior Lecturer
Dept. of Philosophy
Simon Fraser University
You keep leaving out the most important issue --- the unvaccinated young children in the homes / communities of SFU Staff, Faculty, TAs, Grads and many Undergrads. Let's do the risk assessment using current study data.
So by your stat guess, you said vaccines are 75 to 95% effective against breakthrough cases.
And surely the best science finding is that they are typically over 99% effective against hospitalization and death. That is great. However the worst science finding of Covid is the somewhat recent discovery that those with these mild
or asymptomatic breakthrough cases can transmit Covid to others.
So let's us 80% from your 75-95% guess, since the vaccine will become less effective as time passes by end of semester and surely we should account for some unvaccinated people in the system.
So there are about 50,000 staff,faculty,students at SFU. Using 80% effective, that means 20% breakthroughs cases.
20% of 50,000 is 10,000.
So without the mask mandate (even with a loose vaccine passport mandate) SFU might see 10,000 breakthrough cases. 10,000 people going home or to indoor places with children, most of them with no symptoms able to transmit Covid to the
unvaccinated children at home.
You mentioned not knowing the risk for sure and where is the science ... Well there it is. The risk of 10,000 SFUers going home (or to daycare or ...) and many unknowingly, because they are asymptomatic at the time, possibly infecting
their or other peoples children (younger siblings, sons and daughters). And of course the other big recent science finding is the delta variant is way more negatively significant to young children.
So that is some of the science based evidence for the risk of not having a mask mandate.
Generally these science study results are known, so like here in BC, most Govs/institutions realize it must be this two mandate approach: vaccine usage for longer term ending this, but with masks for the short term because of 1)
breakthrough transmission findings, and 2) there is a delay of months with vaccines effectiveness and adoption. Masks mandates now get us past the big spikes we are in now, to vaccines being the solution.
I am disappointed by the recent statement from SFUFA.
The Provincial Health Officer has abruptly re-imposed a very strict indoor mask mandate, among other requirements. In response, the SFUFA executive has done little more
than call for yet further restrictions on its own members. Driving these positions, seemingly, is a powerful risk-benefit analysis.
Benefit: movement toward Covid-zero. Risk: What risk? It's just a piece of cloth, etc. What's the down side?
It seems to me that the only honest answer to that last question is: "We don't know."
We don't have values for the downsides of this supposedly clear and decisive risk-benefit equation. Do we?
Focussing for the moment solely on the issue of mandatory, extended, and
long-term social masking: Do we know its effect on public health? On mental health? On suicide rates? On relationships? On pedagogy? On cognitive, social, and moral development, especially in young people? Has any of this been measured?
If the answer is "no," then the supposedly no-brainer, "it's the science" analysis is revealed as no such thing.
Instead it's a matter for ordinary judgment. Here's mine:
Next week, we will return to campus facing a virus which, even though
very scary, and even in some new ways, still seems to have an approximately 99% survival rate. Against that virus, we can expect the
vast majority of the university (including me) to be fully and effectively vaccinated. Not 100% immunity, to be sure; but (as far as I understand), between 75% and 95%, iow, pretty darned good. As we get closer
to full vaccination of the population, there will, perforce, be more and more cases among the vaccinated (just because that starts to approximate to almost everybody). However, it seems that we can expect these
cases to be, in general, mild (if not asymptomatic). Demographically, the age
of the main university population (our students) constitutes a further protection. Other minimally-disruptive measures may easily be anticipated: including vaccine boosters, continued social distancing, sanitizing, and ventilation. Finally,
anybody who wants to protect themselves
yet further by wearing a mask, including while teaching, is more than free to do so.
And yet we are accepting, even embracing, a picture of our future in which vaccinated professors are required to teach vaccinated students only from behind a multiplex screen
of masks, panoptic documents, and other coercions.
I find that picture both irrational and disturbing.
James Dougal Fleming
Professor, Department of English
Simon Fraser University
Burnaby/Vancouver,
British Columbia,
Canada.
A grateful mind / By owing owes not
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