Contagious Disease

Modeling the spread of H1N1 in the Internet age

CNN reports that H1N1 is still a problem, particularly in the Southeastern U.S.  Traditionally, epidmiologists model the spread of a contagious disease based on two factors: the transmission rate between people and the frequency of contact between individuals.  A study by  Yoo, Kasajima and Bhattacharya (2010) incorporates a third factor that will affect the spread of a disease:

We modify this standard model to incorporate avoidance response—that is, the idea that the frequency of contact among individuals will itself depend on the prevalence of the disease in the population. Unlike the standard [susceptible-infected-recovered] SIR-model, in our model the attack rate changes over time as disease prevalence changes. We assume attack rate to be the product of three factors: a constant baseline attack rate that represents a “biological” transmission rate; a baseline contact frequency which differs among subgroups; and avoidance response parameters which are influenced by the prevalence rate of the disease.

The avoidance response parameters measure the degree to which individuals decide to forego contact with other people. I am curious how the advent of the internet has affected avoidance response.

The internet helps to disseminate information faster.  Thus more people will be aware of a contagious disease and can change their behavior to avoid others.  On the other hand, one potential downside is that people may become desensitized to pandemic information if one is able to access more information on pandemics worldwide.

On the positive side, the internet allows decreases the marginal cost of staying at home.  Office workers can work online from home with little problem; students may be able to “attend” classes through online meetings through Skype or other software.  You can shop, watch video, and of course read blogs to pass the time.

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