Recent findings from study of incentives, decision-making, and influenza epidemics may offer guidance on public health policy. A team of three researchers at the University of California in Los Angeles, two of them physicists, have found that while family-based vaccination incentives fail to prevent severe epidemics.
A program that allows individuals three free annual vaccinations once they pay for the first may prove effective.
The study modeled three scenarios in which individuals were assumed to make their decisions on whether to vaccinate based on past experience. In the first, no incentives were offered. Vaccination rates would increase following years of epidemic and abruptly drop as people began to skip vaccinations, trusting that their peers would remain healthy. When the proportion of the population vaccinated against influenza is sufficiently low, severe epidemics occur, driving the vaccination rate up again the next year.
In the second and third scenarios, an incentive factored into the decision-making process. One possible incentive offers free vaccination for family members once the head of the household paid for his or hers. Counter-intuitively, the family incentive resulted in more frequent epidemics than the incentive-free case.
The third scenario offered an incentive to individuals, allowing them some number of free vaccinations after they paid for the first year. Above a certain threshold number of free years, the researchers found that severe epidemics do not occur. Using parameters that they believe to be realistic, they found that a minimum of three free years of vaccination may prevent influenza epidemics. -KM