That indicates a good strategy on the part of the virus for propagating the species. I have breathed a sigh of relief when I found out a bug kills people very quickly, like Ebola. "Don't kill the host too soon" is key.
Remember, this virus is the product of research (and recombination) aimed at "enhanced abilities".
Essentially, making SARS more contagious was the goal.
Whether it got out by accident or design, I'm reasonably convinced this is a lab product.
Often, with increased contagion, viruses sacrifice some of their deadliness, which may be why this one usually kills people who are already medically compromised on one or more fronts, and not those who are healthy.