C19 Notes

asymptomatic Covid infections to transmission - Diamond Princess study

Author Topic: asymptomatic Covid infections to transmission - Diamond Princess study  (Read 9664 times)

stog

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On the Diamond Princess 74% (70-78%) of infections proceeded asymptomatically, i.e. a 1:3.8 case-to-infection ratio. Despite the intense testing 53%, (51-56%) of infections remained undetected, most of them asymptomatic. Asymptomatic individuals were the source for 69% (20-85%) of all infections. (CMMID)


https://cmmid.github.io/topics/covid19/asymp-transmission.html
« Last Edit: May 10, 2020, 10:44:20 AM by stog »

stog

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see also https://www.theguardian.com/world/2020/may/30/could-nearly-half-of-those-with-covid-19-have-no-idea-they-are-infected

assume >50% asymptomatic
 and then remember those that do go on to show symptoms have already past peak transmissibility density



stog

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asymptomatic cases at 80%
« Reply #2 on: May 31, 2020, 06:40:11 PM »
a colleague from Cyprus tells me

Quote
in Cyprus where more tests are done by percentage of population,   80 % are asymptomatic 15 % don't need hospitalisation 5 percent need hospitalisation less than 2% die .
  • with more routine testing on the general population  the percentage of asymptomatic cases goes up.

stog

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Re: asymptomatic possibly more infectious
« Reply #3 on: June 25, 2020, 07:22:46 PM »
Perhaps of more practical importance right now is a study that followed up 37 asymptomatic people who had positive PCR tests. This showed they had detectable levels of the virus for longer that those who had symptoms. Asymptomatic people are therefore likely to be more contagious. We also know that pre-symptomatic people, those in the early days following infection with Sars-CoV-2, are also highly contagious. Because we are often not aware that we are infected, measures to ensure social distancing and face covering are crucial when it comes to protecting others.

https://www.theguardian.com/commentisfree/2020/jun/25/viral-immunologist-antibody-tests-covid-19-immuity-coronavirus
« Last Edit: June 25, 2020, 07:36:01 PM by stog »

stog

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the study referred to above is in Nature

https://www.nature.com/articles/s41591-020-0965-6#Sec9

stog

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updated transmission chart

the Nature curve referenced above has now apparently been updated

see attachment below & is still the reason why Covid has such a high R number

in answer to someone:
People's immune systems differ & while someone may not react symptomatically their viral load (density) can be & is sufficient for spread