It's a question of how quickly people start to go back to "normal", working and spending money and eating out, not bunkered in their houses with their 2 years' supply of toilet paper. My friend flew back home to Thailand a few days ago, he sent me a photo from inside the plane and it looked about 25% full. Not as empty, though, as the flight I took from Sydney to the US at the height of the SARS scare. That was less than 10% full. The airport we transited at, in Seoul, was totally empty. Once I got onto internal flights in the US the plane was full.
Airlines are running at a huge loss, considering that they are heavily discounting the few tickets they do sell.
Hotels are also discounting heavily and in some parts of the world (usually those where tourism is a big part of the economy) a lot of hotels are running at less than 10% occupancy where they would normally be full.
We have Chinese restaurants shutting down (permanently) at a steady rate here. Where I work is in the middle of where the well-off Chinese tourists do their holiday shopping (at Gucci, Prada, etc.). Those shops won't be making any money. Not that I care, I do all my clothes shopping at places that are a few steps down from Walmart. But still, it's a hit to the economy.