
Why Don’t Patients Get Sick in Sync? Modelers Find Statistical Clues - IntronExon
https://www.quantamagazine.org/disease-modelers-seek-statistical-clues-to-the-timing-of-symptoms-20180301/
======
jakelarkin
saved you a click:

time distribution follows a log-normal distribution (fat tail to the right)

statistically modeling pathogen progression over tissue spatially (2d, 3d)
seems to confirm the real world distribution

~~~
gwern
The log-normal is an underappreciated distribution. It's _almost_ as common as
the normal distribution, and it shows up a lot in human-relevant stuff. For
example, on the main page now is a bit about 'luck' where the model/simulation
is clearly generating log-normal distributions and all the power-law stuff is
a distraction; many things form a natural 'pipeline' where the normal
variables multiply rather than sum, and so you get a log-normal. A famous
example is Shockley's analysis of scientific productivity:
[https://www.gwern.net/docs/iq/1957-shockley.pdf](https://www.gwern.net/docs/iq/1957-shockley.pdf)
If you are somewhat above-average in getting new ideas, in researching them,
and in publishing them, say, you will wind up producing a lot more than
someone who is just a little below-average across the board. Throw in a
general factor like intelligence or just some inter-correlations, and the skew
will be even more extreme.

For infections, multiplicativity makes a lot of sense. After all, what is an
infection but a virus or bacteria literally being fruitful & multiplying?
Small differences in immune system or the virus affecting its speed of
reproduction or net total in each 'stage', and then a log-normal wouldn't be
too surprising.

~~~
darkerside
It's funny because towards the end of the article:

> As Scott and his colleagues noted in their paper, if a pathogen grows
> exponentially and a population receives a statistically normal distribution
> of exposures to it, then a lognormal distribution of incubation times should
> result

This makes it seem trivially obvious that you would expect a log normal
distribution. I'm conflicted because I'm glad I read an interesting article,
but why was it presented as if there were any surprise or mystery to it?

~~~
xapata
Things that are obvious to one person aren't to another.

~~~
darkerside
Right, and it wasn't something that I knew before reading the article. I
appreciate that. What I don't is that there's a fairly simple and likely
reason those charts look the way they do. The article makes it seem like a
miraculous and unexplained coincidence.

------
th0ma5
Why can't I get two colds at the same time?

~~~
burkaman
You can, but you probably wouldn't notice.

[https://www.ncbi.nlm.nih.gov/pubmed/19633719](https://www.ncbi.nlm.nih.gov/pubmed/19633719)

"Two samples were co-infected with HRV-A and HRV-B or HRV-C. [...] Double or
triple infections with HRV-C and respiratory syncytial virus and/or bocavirus
were diagnosed in 33.3% of the HRV-infected patients, but no correlation with
severity of clinical outcome was observed."

------
tingletech
FWIW, "Sync" is not a place -- by "in Sync" they mean "synchronously". This
confused me for several minutes.

~~~
sp332
It's short for "in synchrony". It's really not an uncommon abbreviation.

~~~
kahnpro
Usually they don't capitalize the S

~~~
B1FF_PSUVM
Title capitalization, e.g.
[http://grammar.yourdictionary.com/capitalization/rules-
for-c...](http://grammar.yourdictionary.com/capitalization/rules-for-
capitalization-in-titles.html)

