Vaccines don't provide immunity from disease for some people. But if most people get vaccinated against a disease, such as measles, then the population achieves "herd immunity," which means that there are so few cases of the disease that even people for whom vaccinations are ineffective are unlikely to contract the disease. An article in the Economist argues that "herd immunity is a classic public good."
a. Do you agree with this statement?
b. The same article argues that there is an incentive to "'free ride' off the contributions of others" by not getting vaccinated. What does the author mean by "free ride"? If the author is correct, what will be the effect of this free riding?
c. Given your answer to part (b), why do most people vaccinate their children against childhood diseases, and why do many adults get vaccinated against influenza?