It's been a while since I last posted about swine flu.  Alas, it is still with us. The most recent data from CDC show that swine flu is still with us and that we should steel ourselves for a heckuva flu season this autumn and winter.  The curve peaks around the middle of June, but this is well past a typical flu season.  The influenza virus apparently does not survive well when the absolute humidity rises as temperatures rise and the air can hold more moisture.  When the weather gets cold again in the northern hemisphere and the absolute humidity drops, the virus will better survive outside of its infected host and transmission will increase.

Here is the epidemic curve as it currently stands:

It reassuringly appears to be tailing off, but in reality, it is just experiencing a summer lull (remember, also, that there is quite a bit of under-reporting at this point).  It should start to pick up in October or so when the bars representing the incident cases will almost certainly dwarf the current ones.  We're working on a number of flu-related projects, including the very precise measurement of within-school contact networks (recently funded by NSF!) as well as a project on perceptions of vaccination and (we hope) the measurement of vaccine opinion clustering.  My collaborator on this project, Marcel Salathé, has a terrific paper with Sebastian Bonhoeffer at ETH on the impact of opinion clustering on infectious disease eradication through vaccination. Their work shows that the standard estimates of necessary vaccination coverage required to protect the population through herd immunity are overly optimistic if people who share anti-vaccination beliefs, and therefore do not vaccinate themselves or their families, cluster in a population.  I will try to update, but I fear it will prove to be a very busy Autumn for me...