At the moment, H7N9 is not at all as widespread as SARS. But if you look at the impact of SARS, it was actually short lived. I quote from Credit Suisse report dated today 16 April:
"Temporary impact of SARS on Chinese economy
Whereas the first known case of SARS in China was detected
in November 2002, the outbreak only gained wider public
attention in late-February 2003. The outbreak peaked in April 2003, and by June, the disease had been largely contained.
"The negative impact on economic activity in China and other Asian economies was thus mainly confined to Q2 2003, and pent-up demand helped drive a sharp rebound in economic activity in H2 2003."
