Some Good Can Come From Swine Flu

A very common ailment in Korean summers and falls is pinkeye (conjunctivitis), and the problem had been getting much worse in the past two years. My Korean co-author tells me, however, that the H1N1 virus has created a positive externality in Korea.
These days, people are encouraged to wash their hands more frequently, and they appear to be doing it. That has sharply reduced cases of pinkeye. On net, I imagine that the economic costs of the swine-flu epidemic exceed the costs of the pinkeye outbreak. Nonetheless, it’s always nice to note the silver lining in an otherwise dark cloud. I wonder how many other examples there are of positive externalities arising out of negative shocks.
(Hat tip: J.L.)