Social trends have a bigger impact on vaccination rates and the spread of illness than we thought, say Harvard scientists. Small changes in how people view a vaccine’s “costs”—meaning side effects, as well as money and convenience – can turn a contained outbreak of an illness into a major epidemic four times the size.
California is in the midst of its worst epidemic of the potentially deadly whooping cough in 50 years – are attitudes and social trends contributing to the spread of the disease?
According to WebMD, it’s likely. The site recently quoted the chief of the California Department of Health’s infectious disease center as saying that the pattern of outbreaks matches with counties – for example Marin County north of San Francisco – where more parents refuse vaccines. According to WebMD, a 2008 study also showed whooping cough outbreaks in parts of Michigan where parents opted their kids out of school immunizations.
The biology team at Harvard used mathematical modeling to show how people imitating and influencing each other through social networks cause big changes in a population’s “herd immunity” to a disease. They also showed that raising the cost of a vaccine causes people to take the “free-riding” stance – relying on other people getting the shots instead.
The article reminded me of my own state of mind during last year’s swine flu outbreak. Getting the vaccine was inconvenient (parents were forming lines outside clinics at 5 a.m.) and the opinions of my friends (and by association, the opinions of their friends) swayed me back and forth about whether to get the shot for my son. In the end I didn’t, but I’m still not exactly clear why — I had a fuzzy sense that there were risks, but it wasn’t based on anything concrete.
That’s the danger, say the researchers. Because the whole system of immunity across the population is fragile. I guess the take away is: talk to your doctor, or whoever you trust to give you sound medical advice and then stick to your guns. Don’t hop on the internet or talk to a neighbor. If enough people do that, they say, we’re all in danger.