
SARS-CoV-2 seroprevalence in healthy blood donors during Covid-19 Milan outbreak - panta
https://www.medrxiv.org/content/10.1101/2020.05.11.20098442v1
======
panta
This study [1] published by Policlinico di Milano found that 4.6% of blood
donors had anti-SARS-CoV-2 IgM/IgG antibodies at the start of the pandemic
(February 24th).

See also these articles (in Italian):

\-
[https://www.policlinico.mi.it/news/2020-05-20/1660/covid-19-...](https://www.policlinico.mi.it/news/2020-05-20/1660/covid-19-anticorpi-
in-1-milanese-su-20-gia-settimane-prima-della-pandemia-la-conferma-in-uno-
studio-del-policlinico-di-milano) \-
[https://www.lastampa.it/cronaca/2020/05/20/news/il-
coronavir...](https://www.lastampa.it/cronaca/2020/05/20/news/il-coronavirus-
gia-diffuso-a-milano-alcune-settimane-prima-dell-epidemia-1.38868265)

[1]:
[https://www.medrxiv.org/content/10.1101/2020.05.11.20098442v...](https://www.medrxiv.org/content/10.1101/2020.05.11.20098442v1)

~~~
paganel
> 4.6% of blood donors had anti-SARS-CoV-2 IgM/IgG antibodies at the start of
> the pandemic

Which would make sense. Inter Milano's player Romelu Lukaku was saying about a
month ago that the vast majority of his teammates (23 out of 25) had already
gotten the virus in January, and that for the Inter - Cagliari match (which
was played on January 26th) one of his teammates had to be substituted off
after only 25 minutes because he couldn't run anymore.

For whatever reasons Inter's officials didn't like his comments and
reprimanded him, but it seems like Lukaku was closer to the truth than many
would have liked to admit a month ago.

~~~
pmachinery
> For whatever reasons

Perhaps because he was making baseless claims about his teammates and tainting
the reputation of the club. He should at least know that players being taken
down by cold or flu is not unusual in football.

2014 Seven players are struck by 'flu symptoms':
[https://www.telegraph.co.uk/sport/football/teams/germany/109...](https://www.telegraph.co.uk/sport/football/teams/germany/10943357/Germany-
hit-by-health-scare-as-seven-players-are-struck-by-flu-symptoms-ahead-of-
World-Cup-quarter-final.html)

2017 Wenger fighting to contain outbreak:
[https://www.dailymail.co.uk/sport/football/article-4296828/N...](https://www.dailymail.co.uk/sport/football/article-4296828/Now-
Arsenal-players-hit-FLU.html)

Feb 2019 'Man flu'[0] sweeps through League Two club:
[https://www.bbc.com/sport/football/47239534](https://www.bbc.com/sport/football/47239534)

March 2019 'epidemic' with eight players:
[https://www.thesun.co.uk/sport/football/8709002/poland-
flu-e...](https://www.thesun.co.uk/sport/football/8709002/poland-flu-epidemic-
milik-piatek-bednarek/)

[0]
[https://en.wikipedia.org/wiki/Man_flu](https://en.wikipedia.org/wiki/Man_flu)

~~~
paganel
> He should at least know that players being taken down by cold or flu is not
> unusual in football.

One could think so, of course, but then how does one explain the fact that
when testing really started in Italy (end of February - actually early March
for footballers, after the Juve - Inter match played on March 9th) not one
football player from Inter tested positive, even though they were in what was
even by then the center of the pandemic in Italy, Milano?

By contrast two Juve players (Dybala and Matuidi) tested positive immediately
after March 9th, plus some other players from Firenze and Genoa. One of the
only reasonable explanations would be that most (if not all) Internazionale
players had already gotten the virus by then and had managed to get rid of it.

And I've heard of that "tainted" argument and for the life of me I couldn't
understand it, being sick (or having been sick) doesn't taint anyone. It
somehow reminds me of the infamous #milanononsiferma hashtag used by Milano's
mayor (among others) at the end of February, people who were thinking that
ignoring actual real stuff for fear of not "tainting" the city (in the mayor's
case) would somehow make things better.

------
ggm
Start is bad. February is two months after back computed patient zero is
deemed to have existed in China. This is "infection demonstrated to exist in
Italy before prior dates we believe"

~~~
vkou
> This is "infection demonstrated to exist in Italy before prior dates we
> believe"

That is an unlikely hypothesis, given that we didn't see an exponential
explosion in deaths, and people going to the hospital until February.

Either:

1\. The virus was for some reason less lethal before February.

2\. Only people who don't show symptoms were catching it.

3\. The serological studies are mostly finding false positives.

My money's on #3.

~~~
ginko
>That is an unlikely hypothesis, given that we didn't see an exponential
explosion in deaths

The unmitigated doubling time of COVID-19 seems to be around 2.5 days. So if
about 1% gets hospitalized and people noticed after 10 or so patients with the
same symptoms (that's before any of them died, mind you) you'd need about 1000
people infected. To go from 1 infected person to 1000 takes log2(1000)=9.96
doublings. So if the doubling time is 2.5 that would be 25 days or over 3
weeks before anyone would notice.

Some of these numbers are a bit of a guess but I'm trying to show that
"exponential explosion" can be very small and slow at the very beginning of an
outbreak.

~~~
rightbyte
The variance in actual increase rate is probably way nosier with fewer
subjects. I.e. in the beginning you can probably hover at a somewhat constant
number of infected for a while before it takes off.

On average an infected person seems to spread it to 2-3 persons, but we don't
know the variance. It could be something like 8/10 spread it to zero persons,
1 to 4 persons and 1 to 16 persons. With low number of infected that would
make the increase very noisy. In fact, it has to be so, otherwise Covid19
would explode everywhere and not be more or less containable. It has to catch
momentum or whatever.

------
lbeltrame
FTR, as the study was conducted on blood donors, it may not be representative
of the whole population of the city. This suggests more than ever the need of
extensive serological testing.

------
jansan
The whole antibody testing looks totally unreliable to me. My wife was tested
COVID-19 positive about 4 weeks ago. So was her boss at a different test
location, so I assume the test was correct. Also she was ill with the typical
symptoms. Meanwhile she has recovered and three days ago she had and antibody
test and the result was negative, not even close to the threshold.

~~~
noodlesUK
Do you happen to know which antibody test Was used? There are a number of
different ones with very different specifications.

~~~
jansan
I was a test against IgG antibodies. The report does not mention the
manufacturer of the test.

------
based2
[https://en.wikipedia.org/wiki/2019_Military_World_Games#Cont...](https://en.wikipedia.org/wiki/2019_Military_World_Games#Controversies)

------
onetimemanytime
So it started before they thought it did.

------
blackrock
The evidence is starting to stack up. Maybe the virus didn’t come from China.

China was just the first to discover it.

If this is true, then all the Western countries took a collective dump on
China, and accused them of spreading the virus.

Some theories and timelines so far:

1) July 2019, a lot of strange pneumonia cases were reported in Virginia. The
symptoms sounds suspiciously like Covid19. Two people die. [1]

2) Three months later, on October 18, 2019, French athletes that attended the
Military World Games in Wuhan reported testing positive for the Covid19
antibodies. They are muzzled, and told to not talk with reporters. [2]

3) December 16, 2019, The first documented hospital admission in China.

4) China investigates, and determines this is a new virus. They report it to
the W.H.O. on December 31, 2019.

5) China checks past records, and determines an earlier infection was on
November 17, 2019. [3] About a month before their previous first known case.

6) A New Jersey mayor tests positive for the antibodies, and claims he got
sick in November 2019, a month before China detected their first known case.
[4]

7) December 27, 2019, A woman in Seattle [5], with no travel history to China,
who tested positive for the antibodies, claims she got sick two days after
Christmas. This is 4 days before China reports the virus to the W.H.O. And
three weeks before Seattle’s first official case.

8) Jan 26, 2020, The Lancet theorizes that the virus did not originate from
the seafood market. [6] Daniel Lucey asserts, “The virus came into that
marketplace before it came out of that marketplace.” Thus, this was not from
Chinese people eating bats.

Conclusion:

We don’t know anything for sure, but the W.H.O. needs to investigate those
Virginia nursing home residents that got sick in July 2019, and test them for
the coronavirus antibodies.

If, and this is a very big if, the virus did not originate from China, then,
the western nations are going to have a very big egg on their faces.
Especially after all their racist attacks against the Chinese people, for
eating bats, and what not. And especially for demanding reparations of
trillions of dollars in damages from China. Are they going to pay up instead?
The mystery continues.

=====

[1] [https://abcnews.go.com/US/respiratory-outbreak-
investigated-...](https://abcnews.go.com/US/respiratory-outbreak-investigated-
retirement-community-54-residents-fall/story?id=64275865)

[2] [https://nypost.com/2020/05/07/athletes-at-world-military-
gam...](https://nypost.com/2020/05/07/athletes-at-world-military-games-may-
have-brought-coronavirus-to-europe/)

[3] [https://www.livescience.com/first-case-coronavirus-
found.htm...](https://www.livescience.com/first-case-coronavirus-found.html)

[4] [https://nypost.com/2020/05/07/new-jersey-mayor-believes-
he-h...](https://nypost.com/2020/05/07/new-jersey-mayor-believes-he-had-
coronavirus-in-november/)

[5] [https://www.seattletimes.com/seattle-news/antibody-test-
resu...](https://www.seattletimes.com/seattle-news/antibody-test-results-
of-2-snohomish-county-residents-throw-into-question-timeline-of-coronaviruss-
u-s-arrival/)

[6] [https://www.sciencemag.org/news/2020/01/wuhan-seafood-
market...](https://www.sciencemag.org/news/2020/01/wuhan-seafood-market-may-
not-be-source-novel-virus-spreading-globally)

~~~
qwerty123457
The virus originated from chinese horseshoe bats. It can't just randomly
teleport to some other country on the other side of the world to start an
outbreak, before existing in human population of China.

~~~
nil-sec
Well no, but also in the US there are research facilities working with
Coronaviruses [1]. I am not advocating for this theory because there is zero
credible evidence for it but there are scenarios that would make this
theoretically possible.

[1]
[https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4797993/](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4797993/)

------
flatfilefan
So the question is what has caused increased deaths if there actually was an
unusual increase compared to previous years at all? Was it something else,
like a multiresistent hospital infection in nursing homes?

~~~
flohofwoe
From the abstract:

> Conclusions: SARS-CoV-2 infection was already circulating in Milan at the
> outbreak start.

It just means that the virus entered the region a few weeks or months earlier
than thought so far (the study started on Feb-24), not that there have been
COVID-19 waves in previous years.

This seems similar to the recent news that the first case in France was
backtracked to December 2019, e.g. the virus was already spreading before the
first cases were discovered:

[https://www.bbc.com/news/world-
europe-52526554](https://www.bbc.com/news/world-europe-52526554)

~~~
dustinmoris
If this is true, wouldn't that mean that the R is in fact not as high as we
believe it is, because it was spreading for longer on a slower rate as opposed
to spreading fast in a shorter time period? If we think that it is still
highly infecious then the only other conclusion can be that we have a much
larger population already immunonised?

~~~
s1artibartfast
Not necessarily. r0 can be much more reliably measured than severity.
hospitalization and death rates give pretty clear picture of doubling time,
but could represent wildly different percents of the overall infections

