>> I'm interested in the proportions of those infected, not those who develop pneumonia.<,
That is an interesting number, which is most informative. However, the WHO data is just on pneumonia patients, so a case mortality rate for all infected would be quite different and not comparable to the historical numbers.
The numbers generated by Canada's National labs in Winnipeg is most illustrative. The found evidence of virus in 40% of probables, 35% of suspect, and 20% of those who failed to meet the case definition for suspect or probable. Since virtually all of the deaths were in the probables, inclusion of suspect or SARS CoV positive with minor or no symptoms lowers the case mortality rate and it lowers it markedly if the number in any category other than probable (pneumonia) are significant.
Most of the milder cases were not well followed. Canada announced something like 120 people positive for the virus but not probable or suspect and these patients didn't even know they were positive, so of course nothing was known about contacts.
That is why SARS will return from a human reservoir (as it did in Surrey, BC). I suspect the number positive for the virus is quite large and new cases will start popping up like popcorn when the weather gets a bit cooler. The outbreak in Surrey was the very tip of the iceberg.
Unfortunately, many of the misconceptions driving SARS awareness (and lifting of restrictions such as sell masked palm civets) are somewhat analogous to the Titanic (full steam ahead without any guidance on the invisible dangers). |
