|A comprehensive system of vaccine development in the U.S. resulted in a reduction of 87 to more than 99 percent in illness from ten vaccine-preventable diseases during the twentieth century. These dramatic successes should not be taken for granted, however, as the vaccine system now faces numerous challenges in manufacturing and development, according to a review article in the May/June issue of Health Affairs.
The U.S. vaccine system is a complex collaboration among government, industry, providers, academia, professional societies and third-party payers that has resulted in record low levels of vaccine-preventable diseases and record high levels of immunizations among children. According to the article, however, problems with vaccine supply, cost and safety threaten to derail the vaccine successes of past decades, and the system faces additional challenges posed by the adult immunization program, the need for adequate research and development and the requirement of biopreparedness.
Walter A. Orenstein, director of the Emory Program for Vaccine Policy and Development and associate director of the Emory Vaccine Center at Emory University was lead author of the article. His research was partly supported by the National Institutes of Health. Co-authors included R. Gordon Douglas, consultant in vaccines, infectious diseases and global health; Lance Rodewald, director of the Immunization Services Division in the National Immunization Program at the U.S. Centers for Disease Control and Prevention (CDC); and Alan Hinman, senior public health scientist, Task Force for Child Survival and Development
In addition to the major reductions in illness during the twentieth century from smallpox, diphtheria, measles, mumps, pertussis, polio, rubella, congenital rubella syndrome, tetanus, and H. influenzae, type b (in children less than 5 years old), new vaccines in the past 10 years for varicella (chickenpox), hepatitis A, and pneumococcal disease have led to significant reductions in disease in young children, including a drop of 92 percent in mortality from chickenpox in children four years and younger.
Despite its successes, the U.S. vaccine system is fragile and needs significant improvements, the authors report. Since 2000, vaccines against nine of the twelve vaccine-preventable diseases of childhood have been in short supply. As of 2004 only four commercial companies produce vaccines for young children, and vaccines for seven of the preventable diseases of childhood are manufactured by only one company. The rising cost of vaccines, due partly to compliance with regulations and liability concerns, threatens the widespread availability of vaccines for children. The most recent estimates (2000) of the cost to develop a new vaccine range from $110 million to $802 million, and five vaccines recently reviewed by the National Vaccine Advisory Committee took from two to twenty-one years from Phase I clinical trials to licensing.
Safety concerns, such as the problem with the rotavirus vaccine in 1998 as well as unfounded and unproven concerns about other vaccines threaten to lead to decreased vaccine coverage and outbreaks of vaccine-preventable infectious diseases. Adult immunizations, while effective, have not been as effective as childhood vaccines. However, even the most effective ones do not have the wide coverage of childhood vaccines.
"Although immunization can be counted as one of the major successes of medicine, the recent short supplies of childhood vaccines and the recent problems with influenza vaccine are a clear sign of the importance of continuing to improve the system for vaccine development and manufacture," Dr. Orenstein emphasizes.