Of course, we wouldn't expect people elsewhere to be any better. A study from New Zealand highlighted in an article in the Baltimore Sun notes how few people made any attempt to cover a a sneeze or cough and how many of those who bothered to try actually did so with a bare hand.
Why would an economist be interested? Both failing to cover a sneeze or cough and covering a sneeze or cough with a bare hand lead to externalities. Different types of externalities but externalties nevertheless.
An uncovered sneeze or cough exposes others to the airborne viruses. A person who covers a sneeze or cough with a bare hand unfortunately does not keep the viruses to himself or herself but can spread them to doorknobs and other things touched.
The unfortunate thing from an economic point of view is that there is no easy way to provide alternative incentives--except perhaps social stigmatism. However, if most people are doing this then it is not clear where the stigma would come from.
Perhaps the best we can hope for is better education about the risks and some way of internalizing the risks--at least to one's own family--and then a spillover from behavior toward one's own family to behavior to others.
If anyone could think of creative incentives that could be used in a cost-effective way to change this behavior, I'd be interested.