Scrutable

I read a lot of stories where someone gets infected, their friends and family are tested, and they find 10 more cases, "most of them asymptomatic".

But is that only because they are currently asymptomatic when the test is done? Or does some substantial percentage of people who catch the virus enough to give a positive test remain entirely (or almost) symptom-free for the next 2-3 weeks until the virus is out of their systems? Do we have research or numbers on that?

sTeamTraen wrote: Sat Sep 19, 2020 9:09 am I read a lot of stories where someone gets infected, their friends and family are tested, and they find 10 more cases, "most of them asymptomatic".

But is that only because they are currently asymptomatic when the test is done? Or does some substantial percentage of people who catch the virus enough to give a positive test remain entirely (or almost) symptom-free for the next 2-3 weeks until the virus is out of their systems? Do we have research or numbers on that?

A substantial number of people have no or mild symptoms. Apologies, no time to dig up links etc.

Note that asymptomatic infections also occur with influenza or colds. But no one cares much about that.

There's a few reports looking at how many cases are mild/asymptomatic. CEBM's list https://www.cebm.net/covid-19/covid-19- ... mptomatic/ includes one ("23 Residents of a Long-Term Care Nursing Facility King County, Washington") that deals with asymptomatic and presymptomatic:

10 (43%) had symptoms, and 13 (57%) were asymptomatic.

Seven days after testing, 10 of 13 asymptomatics developed symptoms

Here's a reference: https://www.eurosurveillance.org/conten ... l_fulltext

13% of infected patients on the Diamond Princess in Japan were asymptomatic

Woodchopper wrote: Sat Sep 19, 2020 6:20 pm Here's a reference: https://www.eurosurveillance.org/conten ... l_fulltext

13% of infected patients on the Diamond Princess in Japan were asymptomatic

And here's a better reference

Proportion of asymptomatic coronavirus disease 2019: A systematic review and meta‐analysis
https://onlinelibrary.wiley.com/doi/10.1002/jmv.26326
"The pooled percentage of asymptomatic infection is 15.6% (95% CI, 10.1%‐23.0%)."

Well a lot of the cases must have been mildly symptomatic then because the percentage of the population with antibodies (something like 7.5% in Lombardy so 750,000 people) isn't just 15% higher than the official number of positive tests (just over 100,000 in Lombardy).

(And it wouldn't be even if you multiplied it by two to try to match the excess deaths instead of the official covid stats on deaths, which are about 17,000.)

Is there maybe a bit of a grey area between asymptomatic and mildly symptomatic too? Especially for symptoms like headache and fatigue, where people might have felt a bit run down but not realised what they had.

AMS wrote: Sat Sep 19, 2020 7:06 pm Is there maybe a bit of a grey area between asymptomatic and mildly symptomatic too? Especially for symptoms like headache and fatigue, where people might have felt a bit run down but not realised what they had.

Sure, I mean, one person's fatigue and muscle ache would be another person's "being awake".

shpalman wrote: Sat Sep 19, 2020 6:49 pm Well a lot of the cases must have been mildly symptomatic then because the percentage of the population with antibodies (something like 7.5% in Lombardy so 750,000 people) isn't just 15% higher than the official number of positive tests (just over 100,000 in Lombardy).

(And it wouldn't be even if you multiplied it by two to try to match the excess deaths instead of the official covid stats on deaths, which are about 17,000.)

But would all the people with symptoms have been tested? I don’t know about Italy but in other places back in March to June people who were sick but didn’t need medical assistance were just told to stay at home and self isolate.

Woodchopper wrote: Sat Sep 19, 2020 8:29 pm

shpalman wrote: Sat Sep 19, 2020 6:49 pm Well a lot of the cases must have been mildly symptomatic then because the percentage of the population with antibodies (something like 7.5% in Lombardy so 750,000 people) isn't just 15% higher than the official number of positive tests (just over 100,000 in Lombardy).

(And it wouldn't be even if you multiplied it by two to try to match the excess deaths instead of the official covid stats on deaths, which are about 17,000.)

But would all the people with symptoms have been tested? I don’t know about Italy but in other places back in March to June people who were sick but didn’t need medical assistance were just told to stay at home and self isolate.

True enough, but it means that they would have known they were sick and been able to isolate and inform their contacts.

Can we use one minus the positive test rate* as a proxy for the converse effect, the proportion of symptomatic individuals who don't have covid?

* Italy records the number of individuals tested as well as the actual number of swabs. It will be a bit confounded by the swabs carried out to check that people who turn out to have antibodies aren't currently still infected.

shpalman wrote: Sat Sep 19, 2020 7:13 pm

AMS wrote: Sat Sep 19, 2020 7:06 pm Is there maybe a bit of a grey area between asymptomatic and mildly symptomatic too? Especially for symptoms like headache and fatigue, where people might have felt a bit run down but not realised what they had.

Sure, I mean, one person's fatigue and muscle ache would be another person's "being awake".

Back in March, I saw several news reports in which the numbers of "mild symptoms" and "hospitalised" equalled the total number of cases. For me, "mild" --- and certainly the kind of "mild" that I would assimilate with "asymptomatic" would mean, at worst, a couple of days with a bit of a temperature, and maybe a slight cough. A cold, in other words.

sTeamTraen wrote: Sun Sep 20, 2020 3:09 pm

shpalman wrote: Sat Sep 19, 2020 7:13 pm

AMS wrote: Sat Sep 19, 2020 7:06 pm Is there maybe a bit of a grey area between asymptomatic and mildly symptomatic too? Especially for symptoms like headache and fatigue, where people might have felt a bit run down but not realised what they had.

Sure, I mean, one person's fatigue and muscle ache would be another person's "being awake".

Back in March, I saw several news reports in which the numbers of "mild symptoms" and "hospitalised" equalled the total number of cases. For me, "mild" --- and certainly the kind of "mild" that I would assimilate with "asymptomatic" would mean, at worst, a couple of days with a bit of a temperature, and maybe a slight cough. A cold, in other words.

As far as I recall, 'mild' means that someone didn't get medical assistance. That'll vary between individuals.

Woodchopper wrote: Sun Sep 20, 2020 7:07 pm

sTeamTraen wrote: Sun Sep 20, 2020 3:09 pm

shpalman wrote: Sat Sep 19, 2020 7:13 pm
Sure, I mean, one person's fatigue and muscle ache would be another person's "being awake".

Back in March, I saw several news reports in which the numbers of "mild symptoms" and "hospitalised" equalled the total number of cases. For me, "mild" --- and certainly the kind of "mild" that I would assimilate with "asymptomatic" would mean, at worst, a couple of days with a bit of a temperature, and maybe a slight cough. A cold, in other words.

As far as I recall, 'mild' means that someone didn't get medical assistance. That'll vary between individuals.

Yup:

https://twitter.com/drphiliplee1/status ... 8160221184

Me. Normally fit and well physician used to working 10 hour days knocked absolutely flat for 6 days, temp 40°C, worst ever headache, couldn't eat, so breathless I almost blacked out walking up a hill I can normally do in under 5 minutes.

This would be classed as "mild".
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Does anyone know people who had or have Covid 19? Noone I know personally does
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