This fits a suspicion I've had about this virus since February. It reminds me of mononucleosis. I was told by my doctor when I got mono in college that the types of viruses that cause the syndrome "mono" (usually epstein barr, but not necessarily) are effective on compromised immune systems in post-adolescents. In other words, mono can be on a campus, and only a few people will "get it", not because they are not exposed to it, but because a healthy immune system eliminates the virus so quickly it never establishes any detectable presence in the body. When people become stressed out and exhausted, however (such as around exam times), their immune system is compromised, and the normally easily-defeated virus can get in and establish. Once established, it's hard to get rid of and causes more serious problems.

This article points out that our new virus friend also moves through subsets of the population. Small numbers of people are moving this thing around. Sounds similar to me. Some people are not reacting with this bug; others are. Most don't get terribly sick; a few do. Stressing the population out and hyping fear are very effective at lowering the effectiveness of our immune systems. Those with the most compromised immune systems (the most stressed) are our reservoir.

Our overblown reaction to this bug is at a minimum having zero effect on its course, and is quite possibly making it even worse. Nice job, guys!