Why Aren't Vaccines Available for All Diseases?
The procedure for developing a vaccine takes many years and even more money, often hundreds of millions of dollars. According to John Bradley, M.D., member of the committee on infectious diseases of the AAP, it's because of this that vaccines are prioritized in this order:
  • Vaccines that fight diseases that cause the most deaths and damage, like meningitis
  • Vaccines that prevent severe diseases like measles and influenza
  • Vaccines, like the one for rotavirus, that prevent significant suffering

Additionally, vaccines are studied and produced by companies, so the return on investment must be significant in order to justify the large expense. Vaccines are currently in development to prevent malaria. The malaria vaccine has been slighted in the past because the financial return was not worth the investment the industry had to make, according to Dr. Bradley. However, the Malaria Vaccine Initiative recently announced the beginning of Phase 1 trials of a new vaccine. The trial is currently underway in Brisbane, Australia.
Another reason that vaccines can be tricky to produce is that some viruses mutate so quickly that traditional vaccines are ineffective. A prime example is the HIV/AIDS virus. Despite these hurdles, there is currently a tremendous movement to develop a vaccine to fight HIV/AIDS.
Credit howstuffworks.com