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.
- Byung-Kwang Yoo, Megumi Kasajima, Jay Bhattacharya (2010) “Public Avoidance and the Epidemiology of Novel H1N1 Influenza A,” NBER Working Paper #15752.
World War I’s Greatest Killer
February 12, 2010 in Books, Contagious Disease | No comments
“It is sometimes called the Great Swine Flu epidemic and sometimes the Great Spanish Flu epidemic, but in either case it was ferocious. World War I killed twenty-one million people in four years; swine flu did the same in its first four months. Almost 80 percent of American causalities in the First World War came not from enemy fire, but from flu. In some units the mortality rate was as high as 80 percent.”
This passage is from an interesting book I am currently reading called A Short History of Nearly Everything by Bill Bryson. An (unfortunately) prescient passage in the book describes a certain flu virus we all became familiar with last summer:
“From time to time certain strains of virus return. A disagreeable Russian virus known as H1N1 caused severe outbreaks over wide areas in 1933, then again in the 1950s, and yet again in the 1970s. Where it went in the meantime each time is uncertain. One suggestion is that viruses hide out unnoticed in populations of wild animals before trying their hand at a new generation of humans. No one can rule out the possibility that the Great Swine Flu epidemic might once again rear its head.“
Tags: Books, H1N1, Influenza, Swine Flu