What Does asymptomatic mean in the case of Covid?

[jb747]

There’s been lots of comment in the media about supposedly asymptomatic cases of covid. But what does this actually mean? Do some people have it illness, it runs its entire course, and they have no ill effects? Or, is there a symptom holiday at some point, before it really kicks into gear?

 

[lovetravellingoz]

Strictly speaking it means they have Covid 19, but are not displaying any symptoms. They will only know that they have (or have had) Covid 19 by getting a positive test result.

Though some medical reports I have read suspect that some of the people who had Covid 19 who are labelled asymptomatic may actually have had some symptoms, but just so mild that they did not notice. ie a slight temperature or headache (as most of us have headaches from time to time).

No ill effects as they have no, or barely no, discernible symptoms.

There also seems to be different views on how infectious that asymptomatic cases are as some believe that their viral loads are less (which may be why they have no or no discernible symptoms). Balancing that is that as they do not know that they can be with other people for extended periods and can mix with other people more. So less infectious, but perhaps more contagious as contact tie and number of people they meet can both be more.

There may also be some who are asymptomatic who are not contagious (ie their viral loads are too low to infect another person) and others who may be. For example young children are rarely though to be transmitters of Covid 19.

Caveat: The above is from what I have read, rather than from what I know first hand.

 

[jb747]

Sorry, probably phrased it badly. And I guess I really should have directly asked one of our doctors.

Whilst I understand that some, and perhaps all, people with the virus show limited symptoms in the early stages, are there some people for who the illness runs its course without any outward sign?

 

[p--and--t]

Sorry, probably phrased it badly. And I guess I really should have directly asked one of our doctors.

Whilst I understand that some, and perhaps all, people with the virus show limited symptoms in the early stages, are there some people for who the illness runs its course without any outward sign?

From what I saw online the Japanese found from the Princess Ship there were Covid infected people with zero symptoms until they mysteriously collapsed from silent pneumonia discovered on CT scans and subsequently tested and found to have Covid. It appears the disease may not manifest (at least in the beginning) in the upper respiratory tract at all and just in the lungs. The patient is totally unaware until it is too late in some cases.

 

[woodborer]

Sorry, probably phrased it badly. And I guess I really should have directly asked one of our doctors.

Whilst I understand that some, and perhaps all, people with the virus show limited symptoms in the early stages, are there some people for who the illness runs its course without any outward sign?

AFAIK, this happens with many bugs. Typhoid Mary was a famous case. Even influenza infects a percentage of people who never exhibit any symptoms.

 

[serfty]

From what I saw online the Japanese found from the Princess Ship there were Covid infected people with zero symptoms until they mysteriously collapsed from silent pneumonia discovered on CT scans and subsequently tested and found to have Covid. It appears the disease may not manifest (at least in the beginning) in the upper respiratory tract at all and just in the lungs. The patient is totally unaware until it is too late in some cases.

There's some mention of that here:

Interesting facts.

Opinion | The Infection That’s Silently Killing Coronavirus Patients (Published 2020)

This is what I learned during 10 days of treating Covid pneumonia at Bellevue Hospital.

www.nytimes.com

Science | AAAS

www.sciencemag.org

 

[lovetravellingoz]

Sorry, probably phrased it badly. And I guess I really should have directly asked one of our doctors.

Whilst I understand that some, and perhaps all, people with the virus show limited symptoms in the early stages, are there some people for who the illness runs its course without any outward sign?

The reports that address your question that I have read all have indicated that yes there are. What % there seems little agreement on and this may be affected by region, race, commodities etc. And some people who did have had it may have had a symptom so slight that at the time that they do not notice it.

You may never even know if you have coronavirus. Here's why

New research suggests there could be a lot of people with COVID-19 who don't even know they have it. That's great for those people, but not so great for everyone else. So how common is it?

www.abc.net.au

COVID-19: What proportion are asymptomatic? - The Centre for Evidence-Based Medicine

Carl Heneghan, Jon Brassey, Tom Jefferson Readers of the blog will be aware that we have little trust in the

www.cebm.net

 

[drron]

Was reading a bit more today about the Diamond Princess.Quite a few had no symptoms and didn't collapse with Pneumonia.Some graphs.
.

So despite the cruise ship being described as a floating petrie dish over 80% on board did not get Covid 19.What seems unusual is that those aged 0-9 had the least % of positives but those 10-19 were more likely to pick it up than those aged 20-69.
Then the percentage of Covid positive cases that had no symptoms.
.

So nearly half had no symptoms.Seeing there were only 12 deaths on board most obviously had no ill effects of the infection.

 

[nutwood]

Something really interesting happening in that 10 -29 bracket. Not sure of the sample size but the younger half were 6 times more likely to have the disease and not show symptoms but, judged by the previous graph, they were more likely to have caught it?
If the figures can be relied on, I wouldn't be rushing to open schools!

 

[RooFlyer]

Something really interesting happening in that 10 -29 bracket. Not sure of the sample size but the younger half were 6 times more likely to have the disease and not show symptoms but, judged by the previous graph, they were more likely to have caught it?
If the figures can be relied on, I wouldn't be rushing to open schools!

First, notice the error bars? Very large for the 10-19 group and quite large for the 0-9 group, except in the second graph where the occurrence was 100%. I imagine the large margin of error is due to low sample numbers. An occurrence of 100% doesn't mean much if there was only one case.

Looking at the margin of error, the results for ages 0-50 in the first group could be statistically almost a dead-heat.

"If the figures can be relied on" - I'm sure it was a good study, so we can rely on the figures, but transferring the conclusions from a single sample group, with such large margin of error in the school-aged group, to the question of opening schools in Australia is a VERY long bow to draw I reckon.

EDIT: here are the numbers in each age group, from the pre-print paper. Very small numbers in the younger age-groups (ONE asympt case out of ONE case in the 0-9 age group and 3 asympt out of 5 cases 10-19!!! ) ... as I thought.

 

[p--and--t]

Something really interesting happening in that 10 -29 bracket. Not sure of the sample size but the younger half were 6 times more likely to have the disease and not show symptoms but, judged by the previous graph, they were more likely to have caught it?
If the figures can be relied on, I wouldn't be rushing to open schools!

The sample size and any bias in the sample would be beneficial to understand the full relevance of the charts. If all the passengers had been tested then the graphs would be very surprising (especially the 20-29 bracket.

If only those who presented with symptoms or we in the same cabin as someone who was ill, the data distribution is less reliable.

 

[Princess Fiona]

First, notice the error bars? Very large for the 10-19 group and quite large for the 0-9 group, except in the second graph where the occurrence was 100%. I imagine the large margin of error is due to low sample numbers. An occurrence of 100% doesn't mean much if there was only one case.

Looking at the margin of error, the results for ages 0-50 in the first group could be statistically almost a dead-heat.

"If the figures can be relied on" - I'm sure it was a good study, so we can rely on the figures, but transferring the conclusions from a single sample group, with such large margin of error in the school-aged group, to the question of opening schools in Australia is a VERY long bow to draw I reckon.

EDIT: here are the numbers in each age group, from the pre-print paper. Very small numbers in the younger age-groups (ONE asympt case out of ONE case in the 0-9 age group and 3 asympt out of 5 cases 10-19!!! ) ... as I thought.


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Cheers. I noticed the very wide confidence intervals earlier but didn’t have time to look up the paper.