On SARS and mortality methodology

Post #98,923 by Silverlock 4/27/03 9:33:21 AM Reply	On SARS and mortality methodology Here's a non-alarmist look at how the numbers are counted that is, nonetheless, alarming as hell. [link\|http://www.nbr.co.nz/home/column_article.asp?id=5753&cid=5&cname=Asia\|Link] The world is only a simple place to the simple.
Post #98,926 by Another Scott 4/27/03 10:45:04 AM Reply	Hmmm. Let's think about this. I'm trying to work this out as I type... As I understand it, he's saying that mortality should be counted as: mortality = deaths / (deaths + recoveries) (1) rather than mortality = deaths / total infections (2) The way I think about diseases like this is, "If I get this disease tomorrow, what are my chances of survival?" Or, what is (1 - mortality)? At any given time, there is going to be a large population that may die or may recover - it's not known what any particular patient's outcome will be until it's over. So taking (2) is going to overestimate my survival rate, and (1) is going to underestimate my survival rate (because detection and treatment gets better over time). So, I guess he's got a point. I haven't kept up with SARS, but IIRC initially they were saying the chance of recovery was very good if one was under 40. AFAIK, the mortality in Canada has been restricted to the elderly (e.g. I heard a couple of days ago on "As it Happens": a Canadian health or government official talking about the death of a 99 year old Canadian from SARS...). If it's stil the case that the young survive, then just listing a global "% mortality" rate is misleading as well. They should instead say something like they were saying last year for West Nile - roughly: "West Nile is dangerous for the elderly and groups with compromised immune systems." (Of course, now they're saying WN can leave lasting neurological damage in those who recover...) Is it still the case that younger people who get it recover (assuming they don't have secondary issues like AIDS)? Thanks for the link. Cheers, Scott.
Post #98,928 by jake123 4/27/03 11:17:56 AM Reply	About Canadian cases About SARS: there have been two of people "in their prime" dying, out of 19 deaths so far, both in their forties. One of them may have had another issue, but one of them was just fine. Also, it's possible the numbers are low; in Canada, if you have SARS and need a respirator you get one. If the cases numbered in the thousands instead of the dozens, that would no longer be true. Rumours out of China paint a very bleak picture indeed; it's entirely possible that the numbers are still fictitious, even as they are pumped up tenfold. I've read that reported cases in Shanghai are two, while the real number is over 600. According to my Chinese housemate (who can no longer go home, even if he wants to; his town is a hot zone) most people there think the state is still covering up true numbers... not out of instructions to do so out of the top but more as force of habit wrt reporting bad news to party bosses. As for West Nile in Canada, it turned out that many people in their prime got it last year, and that most of them have not yet fully recovered. It looks more like a crap shoot than a matter of overall health as to whether you get the full-on encephalitis/meningitis trip that is the worst case scenario with West Nile. --\n-------------------------------------------------------------------\n* Jack Troughton jake at consultron.ca \n [link\|http://consultron.ca\|http://consultron.ca] [link\|irc://irc.ecomstation.ca\|irc://irc.ecomstation.ca] \n Kingston Ontario Canada [link\|news://news.consultron.ca\|news://news.consultron.ca] *\n-------------------------------------------------------------------
Post #98,939 by ben_tilly 4/27/03 12:03:59 PM Reply	Already discussed here [link\|http://z.iwethey.org/forums/render/content/show?contentid=97473\|http://z.iwethey.org...w?contentid=97473] Note that neither method gives correct results for a disease that is on an exponential curve. Cheers, Ben "good ideas and bad code build communities, the other three combinations do not" - [link\|http://archives.real-time.com/pipermail/cocoon-devel/2000-October/003023.html\|Stefano Mazzocchi]
Post #98,949 by Silverlock 4/27/03 1:15:00 PM Reply	Yeah, I should have put this there The article does bring up something that I hadn't considered before. Is the possiblity of less serious cases that are not identified as SARS (because the symptoms don't advance beyond common a cold) real enough to skew the rate upward? The world is only a simple place to the simple.
Post #98,955 by ben_tilly 4/27/03 1:48:39 PM Reply	That possibility looks reasonably slim to me That is one thing that contact tracing does for you. If you have some cases of SARS which are not caught because they do not advance beyond something like a cold, I would still expect to see them infect others. And you would see that in the form of people showing up with SARS and no explainable route of transmission. You might not find the intermediate carrier, but you can infer their existence. We have not inferred their existence yet, so I am inclined to think that they aren't there. This logic assumes that people with mild symptoms can infect others and give them full-blown SARS. That is a big assumption. If they do not infect others, then their existence skews your statistics but it isn't that big a deal. If they infect others but only with a mild form of SARS, that probably means that the bug mutated. Which could actually be good news. A mild form of a disease often can innoculate you against a serious one. (See cowpox vs smallpox.) In which case failure to spot that does not make the epidemic more scary, rather it is a potential opportunity lost... Cheers, Ben "good ideas and bad code build communities, the other three combinations do not" - [link\|http://archives.real-time.com/pipermail/cocoon-devel/2000-October/003023.html\|Stefano Mazzocchi]
Post #100,918 by Steven A S 5/8/03 12:08:52 PM Reply	There already is a mild "mutation" It's called the common cold. It appears that SARS is a mutation of the Coronavirus; the virus responsible for the annoying, but normally non fatal disease which to date has still not been cured by anything short of time and symptom relieving medications. ~~~)-Steven---- "I want you to remember that no bastard ever won a war by dying for his country. He won it by making the other poor dumb bastard die for his country..." General George S. Patton
Post #100,922 by admin 5/8/03 12:18:21 PM Reply	Not really. SARS is a corona virus, yes. But it is radically different from the corona virus that causes the common cold. Regards, -scott anderson "Welcome to Rivendell, Mr. Anderson..."

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