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.