A quick note on the asymptomatic rate for Covid-19:

There is a bogus claim going around that basically says the vast majority of infections remain asymptomatic.

They usually cite this one random Chinese dataset with little-to-no information.
This is used for a few main purposes:

1) To downplay the severity of COVID

"You'll be fine! Most people don't even show symptoms!"
2) To suggest an insanely low IFR

"We miss most of the infections because they are asymptomatic!"
3) To suggest herd immunity is either here or very close

4) To suggest that we don't have to contain the virus

4a) Because it is already too late and Covid is almost over
4b) Because the infections are much more widespread and would therefore be impossible to contain
To the best of my knowledge, there are two meta-analyses that address this.

Here is one that looked at 50155 patients from 41 studies and found:

"The pooled percentage of asymptomatic infection is 15.6% (95% CI, 10.1%‐23.0%). "

Here is another meta-analysis that looked at 94 studies.

"The overall estimate of the proportion of people who become infected with SARS-CoV-2 and remain asymptomatic throughout infection was 20% (95% confidence interval [CI] 17–25)"

Added bonus:

"The pooled proportion of asymptomatic infection among 1152 COVID‐19 children from 11 studies is 27.7% (95% CI, 16.4%‐42.7%), which is much higher than patients from all aged groups."

(I'm guessing children are <= 18 y/o, but not sure)

A note:

Often, people say that the majority of cases are either "mild or asymptomatic"

What they mean by "mild" usually isn't clear. Sometimes it just means anything between showing no symptoms and requiring hospitalization.
A few more studies which sort of hint toward high asymptomatic rates, but have clear issues about why they should not be used to determine asymptomatic rates:

In each thread, I describe the issues.
Yet another nonsense article:


• • •

Missing some Tweet in this thread? You can try to force a refresh

Keep Current with Derrick VanGennep

Derrick VanGennep Profile picture

Stay in touch and get notified when new unrolls are available from this author!

Read all threads

This Thread may be Removed Anytime!


Twitter may remove this content at anytime! Save it as PDF for later use!

Try unrolling a thread yourself!

how to unroll video
  1. Follow @ThreadReaderApp to mention us!

  2. From a Twitter thread mention us with a keyword "unroll"
@threadreaderapp unroll

Practice here first or read more on our help page!

More from @VanGennepD

19 Nov
Not to mention, during their second lockdown, daily cases were being cut in half about every 12 days.

Got double the daily cases? Add ~2 more weeks to their containment timeline.

(Speaking fairly roughly here, but you get the idea)
Their first wave was crushed at an even faster rate than their second, eyeballing it from daily cases. Image
Might as well note here than the timeline for containment is significantly accelerated with a green zone strategy.

Reducing the region-to-region reproductive number has massive benefits.

nature.com/articles/s4200… Image
Read 5 tweets
17 Nov
I understand and agree with many of these points, but I don't think the timeline of 3-5 months is realistic.

With a green zone strategy, many places don't have to do much at all before opening up and living like normal. That is, for them, the duration of lockdown is ~0.
Isaac lean towards getting cases low and keeping R~1.

1) If you can get cases low, you can get them to zero
2) If you can keep R~1, a bit more work gets you to containment
3) This state is highly unstable, as we've seen from dozens of countries.

I don't know if Canadian's will accept what is necessary for zero covid.

1) What makes us think they will accept what is needed to get cases low and then maintain R~1?
2) The probability of Canadians accepting zero covid is dynamic. People are tired of yo-yo lockdowns.
Read 6 tweets

Did Thread Reader help you today?

Support us! We are indie developers!

This site is made by just two indie developers on a laptop doing marketing, support and development! Read more about the story.

Become a Premium Member ($3/month or $30/year) and get exclusive features!

Become Premium

Too expensive? Make a small donation by buying us coffee ($5) or help with server cost ($10)

Donate via Paypal Become our Patreon

Thank you for your support!

Follow Us on Twitter!