The Value of Vaccines: Our Nation’s Front Line Against Infectious Diseases

Clinical Pharmacology & Therapeutics (2010) 88 5, 580–581. doi: 10.1038/clpt.2010.197 We live longer now than ever before. Over the twentieth century, our lifespans increased by more than 30 years, and mortality from most vaccine-preventable infectious diseases in the United States decreased by more than 95%. Death and disability from many infectious diseases that were once common are now almost unheard of in the United States. These achievements can be attributed primarily to the benefits of vaccines. A baby born in the United States today has the potential to be protected against 17 infectious diseases through routinely recommended immunizations across his or her lifespan. In the past century, thanks to vaccines, we have witnessed the eradication of natural infection from smallpox worldwide and the complete elimination of polio and rubella in the United States. Vaccines’ benefits extend beyond the individual. Unlike most therapeutics, vaccines provide protection to entire communities by decreasing transmission of bacteria and viruses to others. Community immunity (the herd effect)—the community protection provided when sufficient numbers of people are vaccinated—has led to steep declines in recent years in chicken pox and pneumococcal disease not only in those vaccinated but in entire communities; vaccination reduces the spread of infectious diseases. Evidence shows that through community immunity the pneumococcal conjugate vaccine (PCV-7), when given to children, has contributed to a decline in new cases of invasive pneumococcal disease in adults. From 1998 to 2003, for every case prevented through direct vaccination, at least two additional cases were prevented among those who were not themselves immunized. Similarly, a recent study reinforces that vaccinating children with influenza diminishes the burden of disease in entire communities. In the United States, nearly all vaccine-preventable diseases of childhood have been reduced by at least 90% and most by 99% when compared with prevaccination periods. A doctor today may never see a case of meningitis due to Haemophilus influenzae type b (Hib). Before the introduction of the vaccine in 1988, this serious infection led to the development of invasive Hib disease in approximately 20,000 children each year. Between 15 and 30% of children with Hib became hearing impaired, and more than 600 children died each year despite the availability of antibiotics. In another example, rubella was officially pronounced eliminated in the United States in 2004, yet during the 1960s many rubella-infected mothers gave birth to babies who were deaf or blind or had heart disease or mental retardation. Altogether, the recommended childhood immunization series prevents approximately 10.5 million cases of infectious illness a year and approximately 33,000 deaths in the United States alone. Worldwide, it is estimated that 3 million lives are saved each year through childhood immunizations. Although vaccination is typically associated with children, the potential value of vaccines extends beyond childhood. In fact, the greatest vaccine-preventable disease burden in the United States is among adults. Nearly 40,000 American adults die each year from vaccine-preventable diseases, primarily as a result of influenza infection in the elderly. This is roughly equivalent to the number of women who die each year from breast cancer. It is estimated that this low vaccine coverage costs the nation $10 billion in preventable health-care costs each year. In addition to low rates of pneumococcal immunizations, only 10% of eligible adult women have had the human papillomavirus (HPV) vaccine; moreover, only 36.1% of all adults were vaccinated against the seasonal flu in 2008. In addition to the medical benefit to the individual and indirect benefit to communities, vaccination also contributes social and economic benefits. Compared with other medical interventions, vaccination programs are considered to be among the most cost-effective health investments available for society. In 2005, the National Commission on Prevention Priorities developed a ranking system to compare valuable clinical preventive services. Childhood immunizations, along with daily aspirin use in adults at high risk for heart disease and tobacco-use screening and intervention, ranked as the most cost-effective preventive measures. Adult pneumococcal immunization and influenza immunization ranked in the top 10. Hepatitis B provides a dramatic example of the value of vaccination over the costs of treating the target disease. Over one million people in the United States are chronic carriers of hepatitis B, which can lead to liver disease, liver cancer, and, ultimately, death. Nearly 5,000 chronic carriers die each year. Vaccination for adults against hepatitis B costs approximately $200 for a complete series of three injections. By contrast, patients with chronic hepatitis B account for an average of $5,000 in health-care service and medication costs each year. If a patient develops liver disease as a result of chronic hepatitis B virus infection, the direct medical cost of treatment is estimated to be $59,308, and patients who require a liver transplant can incur billed charges of up to a quarter million dollars for the first year, as estimated nearly a decade ago. A look at cervical cancer treatment illustrates similar cost savings. Two recently approved HPV vaccines cost approximately $350 for the three-dose series. Prevention and treatment of HPV-related disease cost $4 billion a year in the United States. Published cost-effectiveness studies of HPV vaccination suggest that the cost per quality-adjusted life year (or QALY) saved through vaccination against HPV types 16 and 18 would be in the range of $15,000 to $25,000 per QALY. The cost-effectiveness of vaccines is a central reason for many of the policies in place in the United States today. Indirect costs are also minimized when illness is prevented through vaccination; children miss fewer days of school, and parents have fewer missed workdays. In a 2005 study on the economic impact of routine childhood immunization in the United States, researchers estimated that for every dollar spent, the vaccination program saved more than $5 in direct costs and approximately $11 in additional indirect costs to society. It also minimizes the overuse of antibiotics, which can lead to antimicrobial resistance. In total, it is estimated that routine childhood vaccination programs save nearly $10 billion in direct medical costs and $43 billion in societal costs for each birth cohort. Disease outbreaks can be costly to a community. As an example, foodborne outbreaks of hepatitis A caused by infected food handlers or by consumption of contaminated produce have occurred in the United States. The cost burden on a local community and public health system can be considerable. In one review of 13 outbreak investigations, the costs of hepatitis A outbreaks ranged from $140,000 to $36 million, and the costs per case in an outbreak situation ranged from $3,824 to $200,480. Fortunately, community outbreaks of hepatitis A have declined in frequency as a result of hepatitis A vaccination programs. Globalization has reinforced the need to remain vigilant as emerging infections, such as H1N1 influenza, threaten communities. Additionally, as increasing numbers of people travel, diseases once thought to have been eliminated in the United States can reappear. The viruses and bacteria that cause vaccine-preventable disease and death still exist throughout the world and can be passed on to people who are not protected by vaccines. In 2008, 131 measles cases were reported to the US Centers for Disease Control and Prevention. These cases, which occurred in either travelers who contracted measles overseas or in unvaccinated children, illustrate that our immunization safety net is only as good as the community protection we maintain through high vaccination rates. We need only look at the measles resurgence of 1989 to know the risks of not maintaining high vaccination rates for vaccine-preventable diseases. In that outbreak, between 1989 and 1991, there were 55,000 cases of measles, 11,000 hospitalizations, 120 deaths, and $100 million in direct medical care costs. More recently, in eight countries where immunization coverage had been reduced, incidence rates of pertussis surged and increased up to 100 times the rates in countries where vaccination rates were sustained. The numbers are impressive, but we've come to realize that the public health victory we have witnessed from vaccines has created a public health challenge; the impact of many infectious diseases is no longer apparent, and, to many, the numbers don't speak for themselves. Importantly, an increasing number of parents and patients have begun to question the value and continuing need for vaccines. Protecting our society from debilitating and deadly vaccine-preventable diseases must continue to be a cornerstone of our nation's prevention agenda. To achieve optimal prevention, we must have a public that is confident in our immunization program and that understands the continued benefit of vaccines and the risks—to individuals and communities—of forgoing this vigilance. The authors declared no conflict of interest.