"Vaccination is the most effective medical intervention ever introduced and, together with clean water and sanitation, it has eliminated a large part of the infectious diseases that once killed millions of people." This is a bold claim, made in a recent review by a set of leading vaccine researchers. Yet, they have good reason to make it. Nearly a half million cases of measles were officially reported in the U.S. in 1962 (and the number of unreported cases was substantially higher). By 1968, five years after the introduction of the measles vaccine, the reported incidence of measles was down by 95 percent. The year before the pertussis vaccine was introduced in 1948, there were 150,000 reported pertussis cases; by 1956, that number dropped to zero. Nearly 40,000 people contracted polio in 1955, the year Jonas Salk's oral vaccine was licensed; 10 years later there were only 61 cases. The Centers for Disease Control and Prevention recently estimated that vaccinations have prevented over 700,000 deaths in the U.S. during the last 20 years. On a global scale, smallpox killed millions of people during the 20th century. Thanks to a worldwide vaccination effort, it hasn't killed anyone since the 1970s.
Living in a society where communicable diseases are now only a minor cause of death, it's easy for us to take the stunning success of vaccination for granted. In wealthy countries, the childhood health threats targeted by common vaccinations are largely a thing of the past. After their dramatic transformation of public health in the 20th century, vaccines now seem mundane, preserving the status quo by preventing a resurgence of obsolete diseases. The low-hanging fruit has been plucked, and we now struggle with the hard problems, like HIV. We shouldn't expect new vaccines to match the successes of the past century, should we?
By accounting for the full benefits of a new vaccine—such as fewer disease outbreaks or a more productive labor force—societies will have better incentives to invest in their development and distribution.
Actually, we should expect much more from vaccines in the future. In a series of papers on the prospects for vaccines, published last week in the Proceedings of the National Academy of Sciences, several groups of researchers argue that vaccines aren't even close to exhausting their potential. They are still one of the best tools we have to improve human health.
THE MOST OBVIOUS PLACE where vaccines can do more good is in poor countries that still suffer from diseases that have been solved in wealthy countries. As in the U.S. a century ago, infectious diseases cause about half of all deaths in the poorest countries. While much of this problem will be solved with better nutrition and sanitation, increasing the uptake of established vaccinations is crucial. Since 1980, worldwide measles vaccination has increased from 10 percent of all children to more than 80 percent, and annual deaths from measles have dropped from 2.6 million to just over 120,000. Following an international program of polio vaccination, the number of countries where polio is endemic has dropped from 125 in 1988 to three today. We can still do much good with the low-cost, established vaccines we have on hand.
But Dr. Rino Rappuoli, head of vaccine research at Novartis and one of the world's leading vaccine scientists, argues that there is much untapped potential in new vaccines, if we can find a way to finance it. "The bitter truth is that although vaccines keep people healthy and save money," he says, "fewer and fewer pharmaceutical companies invest in the development of new vaccines." Instead, companies focus on lucrative blockbuster drugs for cancer, heart disease, and diabetes. This is unfortunate because today we understand bacteria, viruses, and the human immune system much better than we did when the major 20th-century vaccines were developed. We have new technology to design and manufacture safer and more effective vaccines, particularly new ones aimed at diseases endemic in developing countries. And vaccines can do much more than fight childhood diseases. They can protect disease-susceptible adults and control outbreaks of antibiotic resistant bacteria. They even have the potential to prevent non-infectious diseases like prostate cancer and Alzheimer's.
Vaccines can do much more to make people healthier around the world, but the problem is that they are not particularly profitable. So how should we pay for them? Researchers at Harvard's School of Public Health argue that part of the solution is to be sure we account for all of the economic benefits of vaccination. We tend to undervalue vaccines "by focusing strictly on a subset of the potential benefits, mainly averted health care spending." A typical cost-benefit analysis doesn't account for the broader economic benefits of a healthy population—benefits that "operate through multiple channels to provide a significant boost to economic growth, which can in turn generate additional resources to invest in health." Wealth certainly helps people live healthier lives with better nutrition, sanitation, and health care. But the benefits also flow the other way—a healthier population makes a society wealthier, as healthy people are more likely to complete their education and lead more productive lives.
By accounting for the full benefits of a new vaccine—such as fewer disease outbreaks or a more productive labor force—societies will have better incentives to invest in their development and distribution. Of course, this kind of broad analysis of the economic benefits of health isn't limited to vaccines, but it is particularly appropriate because vaccines solve a collective action problem. Someone else's high cholesterol doesn't put me at risk, but their antibiotic resistant pneumonia does. Newer vaccines for pneumonia are pricey, and as a result fewer people get them, even though the economic costs of the disease outweigh the price of the vaccine. Recognizing the full economic benefits of pneumonia immunization won't make the vaccine cheaper to produce, but it will help societies justify the resources needed to make it available.
For more than two centuries now, vaccines have been one of our most successful medical treatments. But they're not just an old-fashioned treatment for the diseases of a previous era—they're also key to improving our health in the future.