tag:blogger.com,1999:blog-9959776.post6894203344078073764..comments2024-02-15T04:42:41.606+00:00Comments on James' Empty Blog: A few more thoughts about parameter estimation and uncertainty in epidemic modellingJames Annanhttp://www.blogger.com/profile/04318741813895533700noreply@blogger.comBlogger6125tag:blogger.com,1999:blog-9959776.post-4605508148456408062020-03-26T08:16:44.833+00:002020-03-26T08:16:44.833+00:00"Actually, I'm not sure the South Korea d..."Actually, I'm not sure the South Korea data is inconsistent. They had 120 deaths. If you consider the extreme scenario in the Oxford paper (rho = 0.001) this would suggest about 1.2 million were infected, which is just over 2% of the population. They tested 300000 people and found just over 9000 were infected, which is about 3%.<br /><br />Would seem to then depend on how they were doing the testing. I did see something on Twitter, though, which suggested that they'd identified most of the cases, which would then seem inconsistent with the results in the Oxford paper."<br /><br />South Korea data, cause I live there. (deaths are up to 126)<br /><br />Traced: 357,896<br />Positive 9,137<br />negative 334,481<br />Pending: 14,278<br /><br />Positive rate ~2.6 %<br /><br />Testing is done based on contacts and at risk facilities.<br />Example:<br />"From the call center building in Guro-gu, Seoul, no additional cases were confirmed. The current total is 158 confirmed cases since 8 March. Of the 158 confirmed cases, 97 are persons who worked in the building (11th floor = 94; 10th floor = 2; 9th floor = 1), and 61 are their contacts. The KCDC shared the interim result of their epidemiological investigation in collaboration with Seoul City, Incheon City, and Gyeonggi Province during the monitoring period of 9-22 March. The call center on the 11th floor had the highest infection rate (43.5%), compared to 7.5% and 0.5% for 10th and 9th floors, respectively. There was no confirmed case from other floors. Of the 226 persons identified as family members of the 97 confirmed cases who worked in the building, 34 (15.0%) were infected. Of the 97 confirmed cases, 8 (8.2%) were asymptomatic cases. Of the 16 persons identified as family members of the 8 asymptomatic confirmed cases, no confirmed case was found."<br /><br />Example:<br /> In Daegu, testing has been completed for every person at high-risk facilities. Of the 32,990 test results, 224 (0.7%) were positive results.<br /><br /> <br />Hopefully they will start to Post Positive rates of INBOUND travellers which are driving<br />our positives every day. 51 positives from all travellers landing<br />Inbound travellers are now all tested and quarantined.<br />Same in China.<br /><br /> <br />stevenhttps://www.blogger.com/profile/06920897530071011399noreply@blogger.comtag:blogger.com,1999:blog-9959776.post-5801725594099086532020-03-25T05:31:56.285+00:002020-03-25T05:31:56.285+00:00Here's a more detailed explanation of why the ...Here's a more detailed explanation of why the high Oxford number is not credible. <br /><br />It is an interesting and important fact that during the exponential rise, the proportion ill at any given time is a large fraction of the total who have ever been ill (40% in my modelling, the exact fraction depends on parameters) so in order to get to 50% having had the disease, there would have been a point where about 20% had it at a moment in time (now!). The test stats only ever found under 10% positive even though they were preferentially testing suspect cases.James Annanhttps://www.blogger.com/profile/04318741813895533700noreply@blogger.comtag:blogger.com,1999:blog-9959776.post-77574395585605274382020-03-24T22:21:02.859+00:002020-03-24T22:21:02.859+00:00Well they do suggest antibody testing as a way to ...Well they do suggest antibody testing as a way to check. But I really find it hard to believe we are anywhere close to their high scenarios. There would have been lots of unrelated cases of local transmission far earlier than was actually found in reality. Their analysis doesn't consider this factor at all.James Annanhttps://www.blogger.com/profile/04318741813895533700noreply@blogger.comtag:blogger.com,1999:blog-9959776.post-37045061001519422362020-03-24T21:42:47.314+00:002020-03-24T21:42:47.314+00:00Actually, I'm not sure the South Korea data is...Actually, I'm not sure the South Korea data is inconsistent. They had 120 deaths. If you consider the extreme scenario in the Oxford paper (rho = 0.001) this would suggest about 1.2 million were infected, which is just over 2% of the population. They tested 300000 people and found just over 9000 were infected, which is about 3%. <br /><br />Would seem to then depend on how they were doing the testing. I did see something on Twitter, though, which suggested that they'd identified most of the cases, which would then seem inconsistent with the results in the Oxford paper.<br /><br />Also, presumably one way to check this would be to test a random sample of the population. If the Oxford paper is right, then a large fraction should be infected....and Then There's Physicshttps://www.blogger.com/profile/04758445533849376372noreply@blogger.comtag:blogger.com,1999:blog-9959776.post-24488244238548524662020-03-24T21:08:38.079+00:002020-03-24T21:08:38.079+00:00Well you can always say "aha - lots of people...Well you can always say "aha - lots of people were so mildly affected they weren't tested". But yes I'm sure you are right. On reflection I'm a bit surprised at the naivety of the work - it seems hardly any more advanced than what I was doing, despite the eminence of the team. But I suppose it is worthwhile to see what range of parameters can be compatible with the data they considered, rather than just assumign 1% like so many others. But still they could have considered more challenging data!James Annanhttps://www.blogger.com/profile/04318741813895533700noreply@blogger.comtag:blogger.com,1999:blog-9959776.post-49222998877906764022020-03-24T21:01:13.007+00:002020-03-24T21:01:13.007+00:00Doesn't the South Korean data largely contradi...Doesn't the South Korean data largely contradict the assumption in the Oxford paper? As far as I can see, they assume (as I think you say) that only a small fraction of the population are likely to get a severe case and that a fraction of this population will then die. Hence, when you fit to the current data, you get a large fraction that must already be infected. <br /><br />From what I found, South Korea reported just over 9000 cases with 120 deaths. If the result in the Oxford paper is correct, then it would seem to suggest that many more were infected than reported. However, my understanding was that the testing in South Korea was quite thorough, so this seems rather unlikely....and Then There's Physicshttps://www.blogger.com/profile/04758445533849376372noreply@blogger.com