Because many cases against vaccines involve claims of permanent injury to children, they not only are difficult to argue, but can be expensive. With this in mind, the pharmaceutical companies that make vaccines began to
shift their calculus. The drug-development process is costly and time-consuming, and not likely to be embarked upon without a high-likelihood payoff for a drug company’s shareholders. Developing a novel vaccine that could prevent hundreds of thousands of cases of a deadly disease—but cause a much smaller number of side effects that could lead to multimillion-dollar lawsuits—made a useful product an unappealing business proposition. During the 1970s and ’80s, some manufacturers began to withdraw from vaccine production.
In the midst of this, public-health officials grew concerned about the stability of the country’s continued supply of existing vaccines—and the dwindling business incentive for companies to invest in developing new ones. It was on these grounds that Congress passed the National Childhood Vaccine Injury Act of 1986 (also known as the Vaccine Act), indemnifying drug companies from further lawsuits.