8 ms·

Epidemiologist here: you're right. Testing resources are in short supply, so testing is being performed to guide clinical decisions (ie sick people) rather tha

Epidemiologist here: you're right. Testing resources are in short supply, so testing is being performed to guide clinical decisions (ie sick people) rather than public health/science (ie random sample). The handful of serosurveys that have been performed have been quite valuable, but there aren't nearly enough. Hopefully this changes as testing capacity ramps up.

ggm 6y ago
Follow up question: are you guys seeing a drop in norovirus, rotovirus and D&V? I would expect social distancing has reduced opportunistic infection rates: no swimming pools, less interactions at large.
- bjoli 6y ago
  the Swedish state epidemiologist used that measure as a way of measuring the effectiveness of the social distancing and quarantine measures. apparently, the number of people receiving hospital treatment or dying from yearly virus infections like the flu has dropped significantly.
- neilwilson 6y ago
  I have anecdotal evidence from a hospital saying that wards usually reserved for norovirus and C. difficile at this time of year have not been required this year due to the lack of those infections.
nibles_and_bits 6y ago
Do you have any insight into the validity of the Nasopharyngeal covid19 PCR test? I suspect I got a false negative. Get to have a "conversation" with HR tomorrow since I am essential.
- projektfu 6y ago
  For samples with coronavirus particles, sensitivity and specificity are around 100%. (1) The issue is that many samples do not contain virus. As far as I know, that has not been quantified outside of China. (2) 1. https://www.fda.gov/media/136151/download https://www.fda.gov/media/136151/download 2. https://www.mdmag.com/medical-news/comparing-rt-pcr-and-chest-ct-for-diagnosing-covid19 https://www.mdmag.com/medical-news/comparing-rt-pcr-and-ches...
  - dogma1138 6y ago
    Single swab tests may be inaccurate, nasal, throat and anal swabbing is usually recommended for good coverage. The PCR test itself has near 100% sensitivity and specificity when done correctly. Poor swabbing or contamination can result in false negatives or positives. Manual PCR testing is known to be quite prone to human errors hence why the all in one cassette kits are quite popular.
SiVal 6y ago
When the clinical demand wanes, I hope there will be extensive antibody testing in various regions to do a comparison between how many people actually got it vs. how much damage it did. If, as I suspect, there are significant differences (ex: almost everyone in this town seems to have the antibodies, but nobody died, vs. a third of these people have the antibodies, but a lot of people died), we might be able to learn things such as which public policy decisions mattered most and maybe even which ethnicities are more vulnerable or resistant genetically. If a genetic variation is found, it might even lead to a new generation of preventative therapies that go beyond vaccines to shield people against viruses that don't even exist yet.
- bilbo0s 6y ago
  Not really. There are a million reason for differences like that, without studying the problem extremely carefully, you'll never know which of those reasons was consequential. For instance, more people may die in a certain city because there is more pollution in the air, or the concentration of fluoride in the city's water supply is higher, or maybe that city houses a large meat packing plant and an abnormally large number of residents had to roll the dice and work throughout the lockdown. The number of possibilities are nearly endless, and you'd need to eliminate them prior to drawing any conclusions. Even ethnically, you can't really draw any conclusions. Were people of this ethnicity or that ethnicity more likely to be essential Walmart stockboys than others? That one little detail can have an enormous impact on medical outcomes depending on the contagiousness of a pathogen like covid-19. To draw any reasonable conclusions, you'd really need far more than just a comparison between regions, because the different regions have such different public health needs and environmental realities. You'd even need more than a simple comparison between ethnicities. You would need to go wayyy more deep. But I can guarantee that researchers will dig deep to find anything that can be used attack similar pathogens in the future.
  - xscott 6y ago
    > without studying the problem extremely carefully, you'll never know[...] It seems likely to me that this problem will get studied extremely carefully.
xscott 6y ago
I really appreciate this answer, and as a lay person, it helps me put some pieces together in my mind. I suspect there are at least four reasons for testing, and they all benefit from better results, but two of these need good quality unbiased general statistics, and the other two only need high confidence negative/positive results for specific cases: - Policy makers weighing the strategic pros/cons to orders for the public - Individuals (either frightened or skeptical) weighing their decisions - Physicians treating patients - Quarantining people based on contact tracing
Reelin 6y ago
Can surveillance testing not be done using standard laboratory reagents (ie not FDA approved)? (I suppose the rather invasive sample collection protocol might pose a bit of an issue though.)
- dogma1138 6y ago
  Some studies are looking into performing tests on sewage to estimate the number of infected people in an area. There are ways of doing population wide testing that are not very invasive.
gitgudnubs 6y ago
Foolish. Short-sighted. Informed policy was, and is, more important than a couple thousand more clinical tests. If policy had been informed, the number of people saved would have out-weighed the handful who died due to missing out on a test.
- Jommi 6y ago
  Hard to make this decisions in smaller contacts when you are potentially endanger real patients needing care right now Vs future "less dead" estimations.
  - ImprovedSilence 6y ago
    At this point do we even need to test most of the serious cases. if it walks like a duck, quacks like a duck, coughs like a duck, it's a duck. Didn't China start counting cases based on CT scans at one point too?
    - ironic_ali 6y ago
      China is not forthcoming with the truth, at all.
  - gitgudnubs 6y ago
    Health systems deal with scarcity on a daily basis. There's no room for the emotional hand-wringing you're describing. Moving scarce resources from diagnosis patients to studying the population during a pandemic will be one event in a causal chain that results in deaths. It also prevents the outbreak from spreading beyond control. Several orders of magnitude more people have been killed by uninformed policy than would have been killed by redirecting a portion of tests. What kind of MONSTER chooses for so many more people to die?!?
- sorenjan 6y ago
  If you don't test a patient that's positive and put them with other patients and unprotected health personnel you'll infect others and significantly weaken the hospital's ability to treat patients. If you don't test a patient that's negative and put them with covid patients they risk getting infected, taking up an extra ICU spot, and might die. Would you want one of your loved ones in that position? What would change in public policy with more randomized tests?
t2riRXawYxLGGYb 6y ago
Soooo.... - SARS started out with a similar <4% estimated fatality rate and was then revised upwards to anywhere from 9-15% later. - COVID-19 is caused by a different strain of the same virus as SARS. - The CFR of SARS and COVID-19 appear to be very similar, and more notably, appeared by be very similar when we had around 8,000 infections which is where SARS ended. (Similar meaning the CFR hovers between 4% and 20% of closed cases.) How are we so sure that this is any less deadly than SARS? The above suggests to me one of the two is likely to be true: 1. There could have been many more undetected cases of SARS than we knew about, indicting an IFR much lower than it's recorded CFR. 2. COVID-19 could actually end up having an IFR that is similar to SARS (~10%). But of course, I am no epidemiologist, so I assume there's a flaw in my logic. Did I miss something, or is this pretty much the same disease as SARS but with a higher R0?
- capkutay 6y ago
  There's little to no data that backs up your guess. Studies on COVID-19 estimate that the true IFR is somewhere between 0.1% to 0.39%...why? Because the more we test, the more we find asymptomatic and mild cases. And we're yet to even do the type of serological testing that would give us such a decisive sample. Yet we're ALREADY seeing data that suggests that the IFR is lower than SARS and asymptomatic cases/transmission are common. [0] I never read anything about SARS being mild or asymptomatic in the majority of patients...in fact it was the opposite. It was so severely symptomatic that the virus killed itself with natural selection. If you had SARS-COV-11 and exhibited high viral load, you were likely too sick to go spread it. The only serological testing they did on SARS-COV-1 deemed asymptomatic cases to be uncommon [1]. Quite the opposite of COVID-19. 0: https://www.cebm.net/covid-19/global-covid-19-case-fatality-rates/ https://www.cebm.net/covid-19/global-covid-19-case-fatality-... 1: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3035549/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3035549/
  - t2riRXawYxLGGYb 6y ago
    This is good news. Thank you.
bioinformatics 6y ago
Did we miss the chance of going deeper on the Diamond Princess? Maybe a full, in depth check on everyone in the ship would be the ideal approach.
- thu2111 6y ago
  Everyone on the Diamond Princess was checked. That's why it keeps being cited as a closed population with statistically valid sampling (100%). It's the re-projections from that ship onto the age range of the general population that yields low fatality rates comparable to flu.
  - sjg007 6y ago
    If I was on the diamond princess during this outbreak and in a balcony room, that balcony door would have been wide open the entire time.
  - nullc 6y ago
    > . It's the re-projections from that ship onto the age range of the general population that yields low fatality rates comparable to flu. Using old data that misses fully half of the deaths so far... (and there are still people in serious condition). For SARS resolved CFR was a more accurate estimator at all points in time: https://academic.oup.com/aje/article/162/5/479/82647 https://academic.oup.com/aje/article/162/5/479/82647
adelHBN 6y ago
We clearly saw this coming. In fact, in 2006 President Bush signed “National Strategy For Pandemic Influenza, Implementation Plan”, Homeland Security Council, May 2006. As an epidemiologist, what do you think went wrong? How come we are caught off guard? Here is a comparison of our policies and fight against the Spanish flu and Covid-19. Remarkable how stay-at-home and social distancing policies worked then too. https://thepeel.news/stay-at-home-orders-worked-a-century-ago/#1585776766546-96e9aadf-5bc9 https://thepeel.news/stay-at-home-orders-worked-a-century-ag...
- todd8 6y ago
  My grandparents were dating at the time of the Spanish flu. They lived in a little town in the middle of Iowa and practiced social distancing by having their dates at my Grandmother's home, doing quilting, instead of socializing with others.
rstuart4133 6y ago
It strikes me that R0 could be a very rubbery figure because surely it's dependent on the social setting. An R0 of kids crawling over each other in a kindergarten must be different to an retired estate where most people spend their time in their own house. The final R0 is I guess is how all those values average out in a society. Is it normal for all the different societies around the planet to have the same values?
- ignoramous 6y ago
  R0 is the expected number of cases generated by one infected case in a susceptible population. Usually derived through mathematical models, it is not a measure / rate of transmittablity or infectivity of the pathogen, but an indicator used to predict severity: R0 <= 1 implies the disease is endemic, otherwise; an epidemic. R0 is dependent on parameters taken into consideration and the model itself. R0 makes sense only in the context laid out by the model. > An R0 of kids crawling over each other in a kindergarten must be different to an retired estate where most people spend their time in their own house. Ref: https://news.ycombinator.com/item?id=22818413 https://news.ycombinator.com/item?id=22818413 > The final R0 is I guess is how all those values average out in a society. See: https://en.m.wikipedia.org/wiki/Basic_reproduction_number#Notes https://en.m.wikipedia.org/wiki/Basic_reproduction_number#No...
rapidslowness 6y ago
Study from the first community transmission center in Germany. Brand new. https://www.land.nrw/sites/default/files/asset/document/zwischenergebnis_covid19_case_study_gangelt.pdf https://www.land.nrw/sites/default/files/asset/document/zwis... Preliminary results and conclusions of the COVID-19 Case Cluster Study (Gangelt municipality) Prof. Dr. Hendrik Streeck (Institute for Virology) Prof. Dr. Gunther Hartmann (Institute for Clinical Chemistry and Clinical Pharmacology, Speaker of the Cluster of Excellence ImmunoSensation2) Prof. Dr. Martin Exner (Institute for Hygiene and Public Health) Prof. Dr. Matthias Schmid (Institute for Medical Biometry, Informatics and Epidemiology) University Hospital Bonn, Bonn, 9 April 2020 Background: The municipality of Gangelt is one of the places in Germany most affected by COVID19 . It is assumed that the infection is due to a carnival session on 15 February 2020, as several people tested positive for SARSCoV2 in the aftermath of this session. The carnival session and the outbreak of the session are currently being investigated in more detail. A representative sample was taken from the community Gangelt (12,529 inhabitants) in the Heinsberg district. The World Health Organization (WHO) recommends a protocol in which, depending on the expected prevalence, 100 to 300 households are randomly examined. This random sample was coordinated with Prof. Manfred Güllner (Forsa) to ensure its representativeness. Aim: The aim of the study is to determine the status of SARS-CoV2 infections (percentage of all infected persons) in the community of Gangelt, which have been and are still occurring. In addition, the status of the current SARS-CoV2 immunity shall be determined. Procedure: A serial letter was sent to about 600 households. In total, about 1000 inhabitants from about 400 households took part in the study. Questionnaires were collected, throat swabs taken and blood tested for the presence of antibodies (IgG, IgA). The interim results and conclusions of approx. 500 persons are included in this first evaluation. Preliminary result: An existing immunity of approx. 14% (antiSARS-CoV2 IgG positive, specificity of the method >.99 %) was determined. About 2% of the persons had a current SARS-CoV-2 infection detected by PCR method. The infection rate (current infection or already been through) was about 15 % in total. The case fatality rate in relation to the total number of infected persons in the community of Gangelt is approx. 0.37 % with the preliminary data from this study. The lethality rate currently calculated in Germany by Johns-Hopkins University is 1.98 %, which is 5 times higher. The mortality in relation to the total population in Gangelt is currently 0.15 %. Preliminary conclusion: The lethality calculated by Johns-Hopkins University is 5 times higher than in this study in Gangelt, which is explained by the different reference size of the infected persons. In Gangelt, this study covers all infected persons in the sample, including those with asymptomatic and mild courses. In Gangelt, the proportion of the population that has already developed immunity to SARS-CoV-2 is about 15%. This means that 15% of the population in Gangelt can no longer become infected with SARS-CoV-2, and the process has already begun until herd immunity is achieved. This 15% of the population reduces the speed (net reproduction rate R in epidemiological models) of a further spread of SARS-CoV-2 accordingly. By adhering to strict hygiene measures, it can be expected that the virus concentration in a person infected can be reduced to such an extent that the severity of the disease is reduced, while at the same time immunity is developed. These favourable conditions are not given in the case of an exceptional outbreak event (superspreading event, e.g. carnival session, après-ski bar Ischgl). With hygiene measures, favourable effects with regard to total mortality can be expected. We therefore expressly recommend implementing the proposed four-phase strategy of the German Society for Hospital Hygiene (DGKH). This strategy provides for the following model: Phase 1: Social quarantine with the aim of containing and slowing down the pandemic and avoiding overloading critical supply structures, especially the Health care system Phase 2: Beginning of the withdrawal of quarantine while ensuring hygienic conditions and behaviour. Phase 3: Lifting of the quarantine while maintaining the hygienic conditions Phase 4: State of public life as before the COVID-19 pandemic (status quo ante). (Statement of the DGKH can be found here: https://www.krankenhaushygiene.de/ccUpload/upload/files/2020\_03\_31\_DGKH\_Einl https://www.krankenhaushygiene.de/ccUpload/upload/files/2020... adug_Lageeinschaetzung.pdf) Note: These results are preliminary. The final results of the study will be published and presented to the public as soon as they are available.

ggm 6y ago

Follow up question: are you guys seeing a drop in norovirus, rotovirus and D&V? I would expect social distancing has reduced opportunistic infection rates: no swimming pools, less interactions at large.

bjoli 6y ago
the Swedish state epidemiologist used that measure as a way of measuring the effectiveness of the social distancing and quarantine measures. apparently, the number of people receiving hospital treatment or dying from yearly virus infections like the flu has dropped significantly.
neilwilson 6y ago
I have anecdotal evidence from a hospital saying that wards usually reserved for norovirus and C. difficile at this time of year have not been required this year due to the lack of those infections.

nibles_and_bits 6y ago

Do you have any insight into the validity of the Nasopharyngeal covid19 PCR test? I suspect I got a false negative. Get to have a "conversation" with HR tomorrow since I am essential.

projektfu 6y ago
For samples with coronavirus particles, sensitivity and specificity are around 100%. (1) The issue is that many samples do not contain virus. As far as I know, that has not been quantified outside of China. (2) 1. https://www.fda.gov/media/136151/download https://www.fda.gov/media/136151/download 2. https://www.mdmag.com/medical-news/comparing-rt-pcr-and-chest-ct-for-diagnosing-covid19 https://www.mdmag.com/medical-news/comparing-rt-pcr-and-ches...
- dogma1138 6y ago
  Single swab tests may be inaccurate, nasal, throat and anal swabbing is usually recommended for good coverage. The PCR test itself has near 100% sensitivity and specificity when done correctly. Poor swabbing or contamination can result in false negatives or positives. Manual PCR testing is known to be quite prone to human errors hence why the all in one cassette kits are quite popular.

SiVal 6y ago

When the clinical demand wanes, I hope there will be extensive antibody testing in various regions to do a comparison between how many people actually got it vs. how much damage it did. If, as I suspect, there are significant differences (ex: almost everyone in this town seems to have the antibodies, but nobody died, vs. a third of these people have the antibodies, but a lot of people died), we might be able to learn things such as which public policy decisions mattered most and maybe even which ethnicities are more vulnerable or resistant genetically. If a genetic variation is found, it might even lead to a new generation of preventative therapies that go beyond vaccines to shield people against viruses that don't even exist yet.

bilbo0s 6y ago
Not really. There are a million reason for differences like that, without studying the problem extremely carefully, you'll never know which of those reasons was consequential. For instance, more people may die in a certain city because there is more pollution in the air, or the concentration of fluoride in the city's water supply is higher, or maybe that city houses a large meat packing plant and an abnormally large number of residents had to roll the dice and work throughout the lockdown. The number of possibilities are nearly endless, and you'd need to eliminate them prior to drawing any conclusions. Even ethnically, you can't really draw any conclusions. Were people of this ethnicity or that ethnicity more likely to be essential Walmart stockboys than others? That one little detail can have an enormous impact on medical outcomes depending on the contagiousness of a pathogen like covid-19. To draw any reasonable conclusions, you'd really need far more than just a comparison between regions, because the different regions have such different public health needs and environmental realities. You'd even need more than a simple comparison between ethnicities. You would need to go wayyy more deep. But I can guarantee that researchers will dig deep to find anything that can be used attack similar pathogens in the future.
- xscott 6y ago
  > without studying the problem extremely carefully, you'll never know[...] It seems likely to me that this problem will get studied extremely carefully.

xscott 6y ago

I really appreciate this answer, and as a lay person, it helps me put some pieces together in my mind. I suspect there are at least four reasons for testing, and they all benefit from better results, but two of these need good quality unbiased general statistics, and the other two only need high confidence negative/positive results for specific cases: - Policy makers weighing the strategic pros/cons to orders for the public - Individuals (either frightened or skeptical) weighing their decisions - Physicians treating patients - Quarantining people based on contact tracing

Reelin 6y ago

Can surveillance testing not be done using standard laboratory reagents (ie not FDA approved)? (I suppose the rather invasive sample collection protocol might pose a bit of an issue though.)

dogma1138 6y ago
Some studies are looking into performing tests on sewage to estimate the number of infected people in an area. There are ways of doing population wide testing that are not very invasive.

gitgudnubs 6y ago

Foolish. Short-sighted. Informed policy was, and is, more important than a couple thousand more clinical tests. If policy had been informed, the number of people saved would have out-weighed the handful who died due to missing out on a test.

Jommi 6y ago
Hard to make this decisions in smaller contacts when you are potentially endanger real patients needing care right now Vs future "less dead" estimations.
- ImprovedSilence 6y ago
  At this point do we even need to test most of the serious cases. if it walks like a duck, quacks like a duck, coughs like a duck, it's a duck. Didn't China start counting cases based on CT scans at one point too?
  - ironic_ali 6y ago
    China is not forthcoming with the truth, at all.
- gitgudnubs 6y ago
  Health systems deal with scarcity on a daily basis. There's no room for the emotional hand-wringing you're describing. Moving scarce resources from diagnosis patients to studying the population during a pandemic will be one event in a causal chain that results in deaths. It also prevents the outbreak from spreading beyond control. Several orders of magnitude more people have been killed by uninformed policy than would have been killed by redirecting a portion of tests. What kind of MONSTER chooses for so many more people to die?!?
sorenjan 6y ago
If you don't test a patient that's positive and put them with other patients and unprotected health personnel you'll infect others and significantly weaken the hospital's ability to treat patients. If you don't test a patient that's negative and put them with covid patients they risk getting infected, taking up an extra ICU spot, and might die. Would you want one of your loved ones in that position? What would change in public policy with more randomized tests?

t2riRXawYxLGGYb 6y ago

Soooo.... - SARS started out with a similar <4% estimated fatality rate and was then revised upwards to anywhere from 9-15% later. - COVID-19 is caused by a different strain of the same virus as SARS. - The CFR of SARS and COVID-19 appear to be very similar, and more notably, appeared by be very similar when we had around 8,000 infections which is where SARS ended. (Similar meaning the CFR hovers between 4% and 20% of closed cases.) How are we so sure that this is any less deadly than SARS? The above suggests to me one of the two is likely to be true: 1. There could have been many more undetected cases of SARS than we knew about, indicting an IFR much lower than it's recorded CFR. 2. COVID-19 could actually end up having an IFR that is similar to SARS (~10%). But of course, I am no epidemiologist, so I assume there's a flaw in my logic. Did I miss something, or is this pretty much the same disease as SARS but with a higher R0?

capkutay 6y ago
There's little to no data that backs up your guess. Studies on COVID-19 estimate that the true IFR is somewhere between 0.1% to 0.39%...why? Because the more we test, the more we find asymptomatic and mild cases. And we're yet to even do the type of serological testing that would give us such a decisive sample. Yet we're ALREADY seeing data that suggests that the IFR is lower than SARS and asymptomatic cases/transmission are common. [0] I never read anything about SARS being mild or asymptomatic in the majority of patients...in fact it was the opposite. It was so severely symptomatic that the virus killed itself with natural selection. If you had SARS-COV-11 and exhibited high viral load, you were likely too sick to go spread it. The only serological testing they did on SARS-COV-1 deemed asymptomatic cases to be uncommon [1]. Quite the opposite of COVID-19. 0: https://www.cebm.net/covid-19/global-covid-19-case-fatality-rates/ https://www.cebm.net/covid-19/global-covid-19-case-fatality-... 1: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3035549/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3035549/
- t2riRXawYxLGGYb 6y ago
  This is good news. Thank you.

bioinformatics 6y ago

Did we miss the chance of going deeper on the Diamond Princess? Maybe a full, in depth check on everyone in the ship would be the ideal approach.

thu2111 6y ago
Everyone on the Diamond Princess was checked. That's why it keeps being cited as a closed population with statistically valid sampling (100%). It's the re-projections from that ship onto the age range of the general population that yields low fatality rates comparable to flu.
- sjg007 6y ago
  If I was on the diamond princess during this outbreak and in a balcony room, that balcony door would have been wide open the entire time.
- nullc 6y ago
  > . It's the re-projections from that ship onto the age range of the general population that yields low fatality rates comparable to flu. Using old data that misses fully half of the deaths so far... (and there are still people in serious condition). For SARS resolved CFR was a more accurate estimator at all points in time: https://academic.oup.com/aje/article/162/5/479/82647 https://academic.oup.com/aje/article/162/5/479/82647

adelHBN 6y ago

We clearly saw this coming. In fact, in 2006 President Bush signed “National Strategy For Pandemic Influenza, Implementation Plan”, Homeland Security Council, May 2006. As an epidemiologist, what do you think went wrong? How come we are caught off guard? Here is a comparison of our policies and fight against the Spanish flu and Covid-19. Remarkable how stay-at-home and social distancing policies worked then too. https://thepeel.news/stay-at-home-orders-worked-a-century-ago/#1585776766546-96e9aadf-5bc9 https://thepeel.news/stay-at-home-orders-worked-a-century-ag...

todd8 6y ago
My grandparents were dating at the time of the Spanish flu. They lived in a little town in the middle of Iowa and practiced social distancing by having their dates at my Grandmother's home, doing quilting, instead of socializing with others.

rstuart4133 6y ago

It strikes me that R0 could be a very rubbery figure because surely it's dependent on the social setting. An R0 of kids crawling over each other in a kindergarten must be different to an retired estate where most people spend their time in their own house. The final R0 is I guess is how all those values average out in a society. Is it normal for all the different societies around the planet to have the same values?

ignoramous 6y ago
R0 is the expected number of cases generated by one infected case in a susceptible population. Usually derived through mathematical models, it is not a measure / rate of transmittablity or infectivity of the pathogen, but an indicator used to predict severity: R0 <= 1 implies the disease is endemic, otherwise; an epidemic. R0 is dependent on parameters taken into consideration and the model itself. R0 makes sense only in the context laid out by the model. > An R0 of kids crawling over each other in a kindergarten must be different to an retired estate where most people spend their time in their own house. Ref: https://news.ycombinator.com/item?id=22818413 https://news.ycombinator.com/item?id=22818413 > The final R0 is I guess is how all those values average out in a society. See: https://en.m.wikipedia.org/wiki/Basic_reproduction_number#Notes https://en.m.wikipedia.org/wiki/Basic_reproduction_number#No...

rapidslowness 6y ago

Study from the first community transmission center in Germany. Brand new. https://www.land.nrw/sites/default/files/asset/document/zwischenergebnis_covid19_case_study_gangelt.pdf https://www.land.nrw/sites/default/files/asset/document/zwis... Preliminary results and conclusions of the COVID-19 Case Cluster Study (Gangelt municipality) Prof. Dr. Hendrik Streeck (Institute for Virology) Prof. Dr. Gunther Hartmann (Institute for Clinical Chemistry and Clinical Pharmacology, Speaker of the Cluster of Excellence ImmunoSensation2) Prof. Dr. Martin Exner (Institute for Hygiene and Public Health) Prof. Dr. Matthias Schmid (Institute for Medical Biometry, Informatics and Epidemiology) University Hospital Bonn, Bonn, 9 April 2020 Background: The municipality of Gangelt is one of the places in Germany most affected by COVID19 . It is assumed that the infection is due to a carnival session on 15 February 2020, as several people tested positive for SARSCoV2 in the aftermath of this session. The carnival session and the outbreak of the session are currently being investigated in more detail. A representative sample was taken from the community Gangelt (12,529 inhabitants) in the Heinsberg district. The World Health Organization (WHO) recommends a protocol in which, depending on the expected prevalence, 100 to 300 households are randomly examined. This random sample was coordinated with Prof. Manfred Güllner (Forsa) to ensure its representativeness. Aim: The aim of the study is to determine the status of SARS-CoV2 infections (percentage of all infected persons) in the community of Gangelt, which have been and are still occurring. In addition, the status of the current SARS-CoV2 immunity shall be determined. Procedure: A serial letter was sent to about 600 households. In total, about 1000 inhabitants from about 400 households took part in the study. Questionnaires were collected, throat swabs taken and blood tested for the presence of antibodies (IgG, IgA). The interim results and conclusions of approx. 500 persons are included in this first evaluation. Preliminary result: An existing immunity of approx. 14% (antiSARS-CoV2 IgG positive, specificity of the method >.99 %) was determined. About 2% of the persons had a current SARS-CoV-2 infection detected by PCR method. The infection rate (current infection or already been through) was about 15 % in total. The case fatality rate in relation to the total number of infected persons in the community of Gangelt is approx. 0.37 % with the preliminary data from this study. The lethality rate currently calculated in Germany by Johns-Hopkins University is 1.98 %, which is 5 times higher. The mortality in relation to the total population in Gangelt is currently 0.15 %. Preliminary conclusion: The lethality calculated by Johns-Hopkins University is 5 times higher than in this study in Gangelt, which is explained by the different reference size of the infected persons. In Gangelt, this study covers all infected persons in the sample, including those with asymptomatic and mild courses. In Gangelt, the proportion of the population that has already developed immunity to SARS-CoV-2 is about 15%. This means that 15% of the population in Gangelt can no longer become infected with SARS-CoV-2, and the process has already begun until herd immunity is achieved. This 15% of the population reduces the speed (net reproduction rate R in epidemiological models) of a further spread of SARS-CoV-2 accordingly. By adhering to strict hygiene measures, it can be expected that the virus concentration in a person infected can be reduced to such an extent that the severity of the disease is reduced, while at the same time immunity is developed. These favourable conditions are not given in the case of an exceptional outbreak event (superspreading event, e.g. carnival session, après-ski bar Ischgl). With hygiene measures, favourable effects with regard to total mortality can be expected. We therefore expressly recommend implementing the proposed four-phase strategy of the German Society for Hospital Hygiene (DGKH). This strategy provides for the following model: Phase 1: Social quarantine with the aim of containing and slowing down the pandemic and avoiding overloading critical supply structures, especially the Health care system Phase 2: Beginning of the withdrawal of quarantine while ensuring hygienic conditions and behaviour. Phase 3: Lifting of the quarantine while maintaining the hygienic conditions Phase 4: State of public life as before the COVID-19 pandemic (status quo ante). (Statement of the DGKH can be found here: https://www.krankenhaushygiene.de/ccUpload/upload/files/2020\_03\_31\_DGKH\_Einl https://www.krankenhaushygiene.de/ccUpload/upload/files/2020... adug_Lageeinschaetzung.pdf) Note: These results are preliminary. The final results of the study will be published and presented to the public as soon as they are available.