[FRIAM] covid question

[Steven A Smith]

> Given that 23-30 percent (US estimated numbers) up to 50 percent (Iceland reported numbers) of Covid positives are asymptomatic:

I believe that "asymptomatic" is a blurry concept in this case.   There
is "presymptomatic" and "subsymptomatic" and "cryptosymptomatic" even
"cosymptomatic".   

Pre:  Everyone, by definition, is presymptomatic when they are first
exposed/infected.   I get the impression that the delay in significant
symptoms showing is somewhat variable (2-10 days?)

Sub:  Everyone has a different level of immune health and symptom
susceptibility.  I might notice a mild fever immediately while you might
not.  It seems that while the scope of symptoms has expanded with
experience/reporting (nausea, blunted taste/smell, etc.), it appears
that not every individual experiences every symptom, and some are more
sensitive to certain symptoms than others.   I'm not prone to fevers, so
I *might* be very quick to notice my fever, for example.  My partner has
somewhat chronic sinus disturbances, so she might have symptoms masked
or false-positived.

Crypto:  My example above might be crypto or co-symptomatic.   An
asthmatic or COPD or ??? might always be short of breath, and stronger
than usual symptoms might be attributed to anxiety.

Co: I don't believe there is any reason one cannot contract multiple
viri at the same time...  the general immune system does seem to be
relevant...  while having an influenza virus might give some Covid-like
symptoms *and* if COVID is contracted, the symptoms might add, the
general immune response to one virus may well help to slow the other one
from getting a foothold.  I don't know of the research in this area...
there must be plenty.   Also, the Kinsa IOT thermometer "health weather
map" is a good example of co-symptoms.


>
> 1) if you have the disease, but do not show symptoms, do you still develop an immunity after some period of time?
This is a good/important question.   My intuition says that we *must*. 
For example, I have had no more than 1 or 2 influenza-like symptom bouts
in the last 5 years while people around me have had 1 or 2 each winter.
  I am not normally a social-distancer (except for hermit-like tendencies) 
>
> 2) If a pregnant woman recovers from the disease, is her immunity passed along to the fetus?
I am pretty sure the placental barrier, for better or worse, inhibits
that (evolution/selection suggests it is for the better in a larger
sense) but I also believe that breast-feeding is one of the mechanisms
for jump-starting the immune system...   I have 2 daughters with one
child each and both are sensitive/aware of these things... I suppose I
could ask them what they know/believe..
> 3) Will a woman who recovers and has immunity, pass that immunity along to any future conceptions?
While there is a lot of new epigenetics reported in the last 10 years, I
think this one falls in the category of 2 above... the prime source of
"inherited" immunity/resistance might be breast-feeding.  Viva La Leche!
> 4) If asymptomatic cases do develop immunity, "herd immunity" will be attained much faster than projected. 
I think the *sub*symptomatic are definitely fitting in this category. 
It seems possible (likely?) that sub-symptomatic is positively
correlated with higher virus-specific immune-system response, but could
also represent general immunology, possibly suppressing/obviating
virus-specific responses?
> But what is the trade-off between the number of people who might be infected by an asymptomatic — and what is the window of time when the person is an infectious agent — and the contribution to herd immunity? Not expressing this last question very eloquently, but hope point is clear.

I think this is what someone will be able to determine forensically
post-apocalypse (sub-apocalypse?) from the myriad experiments underway
in each country/culture... 

BTW - I don't find the EU's multiple-approaches nearly as disturbing as
some seem to.  SE and NL are responding "similarly" to one another, in
spite of moderately different cultures.  NO and DE seem to be somewhat
different from SE and NL,  and FI is "yet another" approach as a
"Nordic" country.     

This begs the issue somewhat of the tension between "globalization" and
"localization?".  I don't think it can be an either/or.   I suspect
Brexiteers and anti-EU and anti-Globalists are reveling in trying to
show how so much free mixing (open-borders, reciprocal relations, etc.)
can be a problem.    But also it shows how quickly
Spain/Portugal/Italy/France/Germany/etc can close or at least closely
regulate their borders IN SPITE of having been EU's up for 20 years?

- SteveS