From: "Randy H" 

It actually may be worse (from Politech:)

----- Forwarded message from Eric Lerner  -----
From: Eric Lerner 
Subject: SARS: statistical evidence for secondary infection
To: politech
Date: Tue, 06 May 2003 22:53:26 -0400
X-Mailer: Mozilla 4.78 [en] (Win98; U) I would like to call attention to
evidence that, it seems to me, points strongly to the existence of a
secondary infectious agent being responsible for the deaths from SARS. I am
researching a feature article on the search for the cause of SARS and did a
statistical analysis of SARS cases and deaths. As I am also a research
physicist, I am experienced in analyzing time series data. The point I
raise may be obvious, but I have not seen it mentioned in the press or on
the web, so I pass it along in the chance that it has been overlooked. I
was struck by the fact that both the number of SARS cases and the number of
SARS deaths lie extremely close to a simple exponential growth rate curve.
But the exponential rate of growth of the deaths is VERY different than
that for the cases. Using WHO data for the last month, the rate of growth
of the caseload is 40% per 10 days, while the rate of growth of the number
of deaths is 78% per ten days. The death curve lies remarkably close to an
exponential curve, with most points within 5% of the curve. Extrapolating
the curve backwards, the Feb. 11 report by the Chinese authorities of 5
deaths on that date also lies on the curve.
In addition to the very different growth rates, the case curve and the
death curve do not intersect the axis at the same date, indicating
different index cases. For the case load, the first case, extrapolating
backwards, would be Aug.1 ,2002, but for the deaths, the first case would
be Jan. 1, 2003 (assuming the first death to come 14 days after that case
started.)
If the data for China alone is used, the deviations are greater, as there
is an admitted understatement of cases and deaths in the period before
April 20, but the general pattern is very similar. Using the Feb. 11
estimate of 300 cases and 5 deaths, the growth rate of cases in China is
38% per 10 days and of deaths 58% per ten days. (The rate of increase of
death is identical if only the last month of data is used.) The index case
from the case curve would be Aug. 10, 2002 and from the death curve Jan.5,
2003.
This data is very consistent with an initial, non-fatal infection starting
in August, and a secondary infection by a different organism, with high
mortality rate, starting in January. By comparing weekly number of deaths
with weekly cases two weeks earlier, it appears that such a secondary
infection has a mortality rate of at least 25% and spreads much more
rapidly that the SARS infection itself, perhaps by a different method. The
widely noted increase in the mortality rate of SARS would then be seen to
be a consequence of the spread of the secondary infection, with more and
more of total SARS patients now having the deadly secondary infection. This
would also explain why patients are showing up in India and Canada with
SARS coronavirus infection, but no symptoms--they have not been infected by
the secondary infection organism.
The data seems to indicate a secondly infection, which requires the SARS
infection first, not a mutation of the SARS virus. Since the secondary
infection, or whatever causes the deaths, is spreading far more rapidly
than the basic SARS infection, if it was an independent cause of the
sysmtpoms, the case load would also begin to increase more rapidly. In Hong
Kong, this certainly does not seem to be the case, as death as a percentage
of two-week-old cases are still rising rapidly, while the overall level of
SARS cases declines. But this behavior would be very consistent with a
secondary infection which can only spread among those who already have the
initial SARS virus.
I admit that the Canadian results, which show the SARS virus positive tests
declining with time could indicate the more pessimistic alternative, that
the secondary infection can spread on its own, without prior infection by
the SARS coronavirus. However, in Hong Kong they appear to be getting
positive coronavirus tests from all SARS patients.

If this hypothesis is valid, there should be an infectious agent that shows
up only in SARS dead and in those who become very sick and need
ventilators(who presumably would die without treatment). Also, it implies
that death rates will rise in mainland China until they reach the levels of
Hong Kong, which is nearly 25%. Eric Lerner
Lawrenceville Plasma Physics
elerner{at}igc.org



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"Rich Gauszka"  wrote in message
news:3eb87aa6{at}w3.nls.net...
> from  http://news.bbc.co.uk/2/hi/health/2992749.stm
>
>       Sars death rate higher than thought
>
>             By Pallab Ghosh
>             BBC Science correspondent
>
>
> The first detailed study of the spread of the Sars virus in Hong Kong has
> discovered that the death rate among sufferers was much higher than
> previously estimated.
>
> The World Health Organization (WHO) initially estimated that the death
rate
> from the virus was 5%.
>
> But the new study - the first to be based on a statistically sound sample
of
> 1,425 cases - puts the death rate at one in five (20%).
>
> One of the scientists leading the study, Professor Roy Anderson of
Imperial
> College, London, said the findings show it is vital that new cases are
> identified and treated quickly in order to control the spread of the
virus.
>
> Scientists fear that the fact that the death rate from Sars appears to be
> higher than first thought may be a sign that the virus is mutating into
more
> deadly forms.
>
> However, it may just be that the WHO under-estimated the risk.
>
> The study, based on the first nine weeks of the outbreak in Hong Kong,
also
> shows that older people are significantly more at risk from the virus.
>
> The death rate is more than 40% for patients aged 60 or over - but just
13%
> for those under 60.
>
> Researchers found that, on average, it takes just over six days for
clinical
> symptoms to show after a person is infected.
>
> Treatment delay
>
> But, crucially, in Hong Kong the norm was for people to seek treatment
> between three and five days after those symptoms began to show.
>
> The delay in seeking treatment - especially early on in the epidemic -
helps
> explain why the disease spread so widely in the territory.
>
> Professor Anderson said: "That period is very, very important, because
once
> clinical symptoms become apparent the patient then is excreting or
exhaling
> the virus and is highly infectious to others.
>
> "Governments need to make sure that patients are encouraged to rapidly
> report symptoms and admit themselves to hospital to arrange for quarantine
> and testing to see whether they have the Sars virus."
>
> The researchers say that efforts to control the spread of the disease have
> successfully slowed the spread of the epidemic.
>
> But they warn there may now be a temptation to ease measures such as
> restrictions on movement - and so prolong the epidemic.
>
> In addition, the coming warm season in Hong Kong brings an increased risk
of
> seasonal dengue fever and influenza outbreaks, which may complicate a
rapid
> diagnosis of Sars.
>
> The new research is published on the website of The Lancet medical
journal.
>
>

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