correct
which is why social distancing has to apply to everyone
Greg
> and therefore no one knows if they are infectious until they have
> symptoms, hence everyone is potentially a risk to others.
>
> Jay
> Dr Jay Ginn
>
>
>> On 21 Mar 2020, at 09:06, Greg Dropkin <[log in to unmask]> wrote:
>>
>> yes, that's their point.
>>
>> I've not yet read references 17 and 18, which may give a clue.
>>
>> I've a dim memory someone said 1 day before symptoms.
>>
>> Best asking on the list
>>
>> Greg
>>
>>> but incubation period ( time between infection and appearance of
>>> symptoms)
>>> does not tell us how soon during that period of, say, 5 days, an
>>> infected
>>> person can transmit the infection.
>>>
>>> Jay
>>> Dr Jay Ginn
>>>
>>>
>>>> On 21 Mar 2020, at 08:26, Greg Dropkin <[log in to unmask]> wrote:
>>>>
>>>> hi Jay, all
>>>>
>>>> yes, before
>>>>
>>>> https://annals.org/aim/fullarticle/2762808/incubation-period-coronavirus-disease-2019-covid-19-from-publicly-reported
>>>> “However, given recent evidence of SARS-CoV-2 transmission by mildly
>>>> symptomatic and asymptomatic persons (17, 18), we note that time from
>>>> exposure to onset of infectiousness (latent period) may be shorter
>>>> than
>>>> the incubation period estimated here, with important implications for
>>>> transmission dynamics.”
>>>> 17 is Chan JF, Yuan S, Kok KH, et al. A familial cluster of pneumonia
>>>> associated with the 2019 novel coronavirus indicating person-to-person
>>>> transmission: a study of a family cluster. Lancet. 2020;395:514-523.
>>>> [PMID: 31986261] doi:10.1016/S0140-6736(20)30154-9
>>>> 18 is Rothe C, Schunk M, Sothmann P, et al. Transmission of 2019-nCoV
>>>> infection from an asymptomatic contact in Germany [Letter]. N Engl J
>>>> Med.
>>>> 2020. [PMID: 32003551] doi:10.1056/NEJMc2001468
>>>>
>>>> Greg
>>>>
>>>>
>>>>> hi greg,
>>>>> do we know for sure when a person starts to become a transmitter, in
>>>>> relation to their awareness of:
>>>>> - fever
>>>>> - new dry cough
>>>>>
>>>>> can it be 1 day before? 2 days before? or is it only after the above
>>>>> symptoms appear?
>>>>>
>>>>> Jay
>>>>> Dr Jay Ginn
>>>>>
>>>>>
>>>>>> On 21 Mar 2020, at 07:30, Greg Dropkin <[log in to unmask]> wrote:
>>>>>>
>>>>>> hi Harry, all
>>>>>>
>>>>>> but you're assuming that the probability that a symptomatic person
>>>>>> contacts a susceptible person is the same as the probability that an
>>>>>> unsymptomatic person does so. I'd assume that when they become
>>>>>> symptomatic, most people (hopefully) self-isolate or at least stay
>>>>>> home.
>>>>>>
>>>>>> however, someone on the list may have read up on transmission routes
>>>>>> -
>>>>>> which is a good question.
>>>>>>
>>>>>> Greg
>>>>>>
>>>>>>> Thanks Greg,
>>>>>>>
>>>>>>> It just seems counterintuitive that those who are symptomatic, i.e.
>>>>>>> literally coughing out infected droplets, are reportedly not
>>>>>>> causing
>>>>>>> as
>>>>>>> many new infections as those who have not yet started coughing.
>>>>>>> Random
>>>>>>> coughs unrelated to the infection might very well be part of the
>>>>>>> answer,
>>>>>>> but it seems counterintuitive that they would spread infection more
>>>>>>> effectively than actual symptomatic coughing? So I suspect
>>>>>>> something
>>>>>>> else
>>>>>>> may be going on and it's piqued my curiosity a bit.
>>>>>>>
>>>>>>> In solidarity,
>>>>>>> Harry
>>>>>>>
>>>>>>>> On Sat, 21 Mar 2020 at 06:37, Greg Dropkin <[log in to unmask]>
>>>>>>>> wrote:
>>>>>>>>
>>>>>>>> hi Harry
>>>>>>>>
>>>>>>>> yes, I think the untested cases are missing, as you say.
>>>>>>>>
>>>>>>>> maybe look here:
>>>>>>>>
>>>>>>>> https://github.com/midas-network/COVID-19/tree/master/parameter_estimates/2019_novel_coronavirus
>>>>>>>> https://midasnetwork.us/covid-19/#resources
>>>>>>>>
>>>>>>>> even if these don't include age distribution (I haven't looked)
>>>>>>>> you
>>>>>>>> might
>>>>>>>> take the US age distribution to see what the CDC age-specific
>>>>>>>> figures
>>>>>>>> would predict for the overall CFR for the US, and compare that
>>>>>>>> with
>>>>>>>> the
>>>>>>>> material above.
>>>>>>>>
>>>>>>>> 2) BBC says "the symptoms start with a fever followed by a dry
>>>>>>>> cough,
>>>>>>>> which can lead to breathing problems. This is a new, continuous
>>>>>>>> cough
>>>>>>>> and
>>>>>>>> means coughing a lot for more than an hour, or having three or
>>>>>>>> more
>>>>>>>> coughing episodes in 24 hours (if you usually have a cough, it may
>>>>>>>> be
>>>>>>>> worse than usual)."
>>>>>>>>
>>>>>>>> So, the fact that someone coughs a few times does not mean they
>>>>>>>> are
>>>>>>>> showing symptoms, or that they have COVID. But if it turns out
>>>>>>>> that
>>>>>>>> people
>>>>>>>> are in fact infectious before showing symptoms (as above), their
>>>>>>>> occasional cough could transmit without signifying infection. No?
>>>>>>>>
>>>>>>>> Further, I'm sure I read somewhere (Andrei maybe?) that they think
>>>>>>>> people
>>>>>>>> are infectious about one day before showing symptoms.
>>>>>>>>
>>>>>>>> Greg
>>>>>>>>
>>>>>>>>> Thanks, Greg,
>>>>>>>>>
>>>>>>>>> So, if I read that correctly, 'all cases' used as the denominator
>>>>>>>>> to
>>>>>>>> calculate the lower bound, includes only 'cases confirmed by state
>>>>>>>> or
>>>>>>>> local
>>>>>>>>> public health laboratories as well as those with a positive test
>>>>>>>>> at
>>>>>>>> the
>>>>>>>> state or local public health laboratories and confirmation at
>>>>>>>> CDC'.
>>>>>>>> That
>>>>>>>> would appear to exclude the untested so probably a fraction of the
>>>>>>>> total
>>>>>>>> number of persons infected, resulting in a vastly inflated CFR?
>>>>>>>>>
>>>>>>>>> As it happens, I have another naive question about a tangentially
>>>>>>>> related
>>>>>>>>> matter. From what I've been reading, the virus is transmitted via
>>>>>>>> droplets
>>>>>>>>> spread through coughing and sneezing, and yet, it seems, most of
>>>>>>>>> those
>>>>>>>> infected got the virus from contact with people who have not yet
>>>>>>>> developed
>>>>>>>>> symptoms, like coughing. Sneezing is not supposed to be a
>>>>>>>>> COVID-19
>>>>>>>> symptom,
>>>>>>>>> anyway. So what's the mechanism?
>>>>>>>>>
>>>>>>>>> Ta.
>>>>>>>>>
>>>>>>>>> In solidarity,
>>>>>>>>> Harry
>>>>>>>>>
>>>>>>>>>> On Fri, 20 Mar 2020 at 20:19, gregd <[log in to unmask]> wrote:
>>>>>>>>>>
>>>>>>>>>> hi Harry, all
>>>>>>>>>> they explain what they mean by "cases" and why / how they
>>>>>>>>>> present
>>>>>>>> ranges, in this para:
>>>>>>>>>> Data from cases reported from 49 states, the District of
>>>>>>>>>> Columbia,
>>>>>>>> and
>>>>>>>> three U.S. territories (5) to CDC during February 12–March 16 were
>>>>>>>> analyzed. Cases among persons repatriated to the United States
>>>>>>>> from
>>>>>>>> Wuhan, China and from Japan (including patients repatriated from
>>>>>>>> cruise
>>>>>>>> ships) were excluded. States and jurisdictions voluntarily
>>>>>>>> reported
>>>>>>>> data
>>>>>>>>>> on laboratory-confirmed cases of COVID-19 using previously
>>>>>>>>>> developed
>>>>>>>> data collection forms (6). The cases described in this report
>>>>>>>> include
>>>>>>>> both COVID-19 cases confirmed by state or local public health
>>>>>>>>>> laboratories as well as those with a positive test at the state
>>>>>>>>>> or
>>>>>>>> local
>>>>>>>>>> public health laboratories and confirmation at CDC. No data on
>>>>>>>> serious
>>>>>>>> underlying health conditions were available. Data on these cases
>>>>>>>> are
>>>>>>>> preliminary and are missing for some key characteristics of
>>>>>>>> interest,
>>>>>>>> including hospitalization status (1,514), ICU admission (2,253),
>>>>>>>> death
>>>>>>>> (2,001), and age (386). Because of these missing data, the
>>>>>>>> percentages
>>>>>>>> of hospitalizations, ICU admissions, and deaths (case-fatality
>>>>>>>>>> percentages) were estimated as a range. The lower bound of these
>>>>>>>> percentages was estimated by using all cases within each age group
>>>>>>>> as
>>>>>>>> denominators. The corresponding upper bound of these percentages
>>>>>>>> was
>>>>>>>> estimated by using only cases with known information on each
>>>>>>>> outcome
>>>>>>>> as
>>>>>>>> denominators.
>>>>>>>>>> Greg
>>>>>>>>>>> On 19/03/2020 23:18, Harry Feldman wrote:
>>>>>>>>>>> I'm still confused about what they're using for denominators?
>>>>>>>>>>> The
>>>>>>>> CSC
>>>>>>>> document gives rates like '10-27%' for the oldest age group, which
>>>>>>>> isn't terribly informative. If they are using 'confirmed cases'
>>>>>>>> for
>>>>>>>> a
>>>>>>>> denominator, then for one thing, shouldn't they be able to pin it
>>>>>>>> down
>>>>>>>>>>> closer than a range of 17 points? And for another, won't that
>>>>>>>> result
>>>>>>>> in an unrealistically high rate?
>>>>>>>>>>>
>>>>>>>>>>> On Fri, 20 Mar 2020 at 09:40, Greg Dropkin <[log in to unmask]>
>>>>>>>> wrote:
>>>>>>>>>>>
>>>>>>>>>>>> Dear Vassilis
>>>>>>>>>>>>
>>>>>>>>>>>> does this do what you want?
>>>>>>>>>>>> https://www.cdc.gov/mmwr/volumes/69/wr/mm6912e2.htm?s_cid=mm6912e2_w
>>>>>>>>>>>>
>>>>>>>>>>>> Greg
>>>>>>>>>>>>
>>>>>>>>>>>>> Dear list, (apologies if this has been covered in previous
>>>>>>>>>>>> discussions)
>>>>>>>>>>>> Can somebody direct me to a source which gives the age
>>>>>>>> distribution
>>>>>>>> of
>>>>>>>>>>>> COVID-19 related deaths (preferably by country or
>>>>>>>>>>>> sub-nationally;
>>>>>>>> and
>>>>>>>>>>>> preferably with real(ish)-time updates)?
>>>>>>>>>>>>>
>>>>>>>>>>>>> I can find information about (much questionable) death rates
>>>>>>>>>>>>> by
>>>>>>>>>>>> age
>>>>>>>>>>>> group
>>>>>>>>>>>>> (e.g.,
>>>>>>>>>>>>>
>>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>
>>>>>>>> https://www.worldometers.info/coronavirus/coronavirus-age-sex-demographics/
>>>>>>>> ),
>>>>>>>>>>>> but I have failed to find anywhere any information on the
>>>>>>>> age-group
>>>>>>>> composition (or age distribution!) of COVID-19 related deaths. The
>>>>>>>> closest
>>>>>>>>>>>>> I have come is the data from Statista
>>>>>>>>>>>>>
>>>>>>>>>>>>
>>>>>>>>>>> (
>>>>>>>>>>
>>>>>>>> https://www.statista.com/topics/5994/the-coronavirus-disease-covid-19-outbreak/
>>>>>>>> ),
>>>>>>>>>>>> giving counts of _cases_ by age and of _deaths_ by
>>>>>>>>>>>> region/country,
>>>>>>>> but
>>>>>>>>>>>> not
>>>>>>>>>>>>> of deaths by age.
>>>>>>>>>>>>>
>>>>>>>>>>>>> Any suggestions?
>>>>>>>>>>>>>
>>>>>>>>>>>>>
>>>>>>>>>>>>> Thanks,
>>>>>>>>>>>>> Vassilis
>>>>>>>>>>>>> ==========================
>>>>>>>>>>>>> Dr Vassilis Monastiriotis
>>>>>>>>>>>>> European Institute, LSE
>>>>>>>>>>>>> ==========================
>>>>>>>>>>>>>
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>>
>>
>
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