The news, announced yesterday, that the coronavirus that began in China is contagious during its incubation period (which can be as long as 11 days) is something that unsettled the bejeezus out of me but I'm not sure most people really get the gravity of that announcement...
Let me add, before I go further, that I'm obviously not a virologist, but my work has led on many occasions to sitting down with epidemiologists to understand their work. That said, I'm a pretty good student. The most important aspect that was drilled into me concerned...
...this very point. To explain by way of comparison: the reason that Ebola hasn't wiped out vast tracts of the population is that, as with many viruses, it's not contagious during its incubation period, and when the symptoms finally do show up, it hits the victim *so* hard...
...that it lays them out pretty fast *and* signals to health professionals what they're dealing with. This limits the distance they can travel and infect others. The nightmare scenario is a virus with a long incubation period during which no symptoms show but it's contagious...
On the one hand, this means screening processes simply don't work. The person can have coronavirus but without fever or other indications, they are not stopped from boarding planes or travel and there's no way to tell they have it. But at the same time, for those 11 days...
...wherever they travel, they have the potential to transmit the virus to others who also won't show symptoms for up to 11 days but are at the same time widening the circle of transmission by infecting others during their own incubation period, submarining the virus from view...
...and if the news reports are correct, it looks like that's what we're dealing with here, which is why it's popping up so quickly in other countries. A person can get infected, spend a couple of days hanging around, get on a plane without symptoms or warning...
...travel clear to the other side of the globe, spend more time, and then the symptoms appear...after which everyone on the route from A to B has been exposed and has at least the *potential* to be hit by it. As opposed to NOT being contagious until symptoms show, at which...
...time the person can quickly be prohibited from traveling or even quarantined. I suspect that this will spread a lot farther, and a lot faster, than anyone would like. So if any cases show up in your area, be doubly sure to disinfect and follow standard health precautions.
Again: not looking to alarm anyone, just to reinforce the need for common sense safeguards and awareness of the situation. If we could (and did) stop smallpox, which some virologists call a "planet sweeper," we can address this, just be careful while they figure it out.
