Vaccine Development in the Twenty‐First Century: Changing Paradigms for Elusive Viruses

Vaccine development and licensure for new viral diseases is a complex enterprise. In the past, pathogenic viruses might have been simply attenuated or inactivated to generate an effective vaccine. Such vaccines had an enormous impact on the spread of common viral diseases and have resulted in extraordinary improvements in personal and public health. However, as the frequency of epidemic disease has receded, public tolerance for adverse effects has diminished. Today, the perceived risk‐to‐benefit ratio for an individual must be lower than ever if a new vaccine is to be acceptable to the public. Even when objective data indicate that adverse events are rare and efficacy is nearly 100%, some vaccines have been anecdotally linked to prevalent disease conditions in popular opinion, creating a perception of harm and evading scientific rebuttal. Clinical Pharmacology & Therapeutics (2009); 86 3, 234–236. doi:10.1038/clpt.2009.128