Perspectives in Health Magazine
The Magazine of the Pan American Health Organization
Special Centennial Edition
Volume 7, Number 2, 2002

Genomics has opened up other entirely new avenues as well. Plants can be engineered to produce antigens, so an edible vaccine is feasible. This would have to be constructed so that either a mucosal adjuvant or some other immune-enhancing factor was also present. Vaccines can also be applied to the skin and, amazingly, find their way into the body, yielding a transdermal vaccine. Here again, immune enhancers will represent the problem area.

Within a 100-year timeframe, many of these ideas will seem clumsy; third and fourth generation developments will then be in use. Special attention will have to be given to noninjectable vaccines--no one wants their babies to become pincushions.

Vaccine combinations will become increasingly important. Some companies are already working on a sevenvalent vaccine against diphtheria, pertussis, tetanus, poliomyelitis, hepatitis B, Hib and meningococcus C all mixed together. A measles-mumps-rubella-chickenpox vaccine is already on the horizon. There is little doubt that a century from now, infants will be protected against most of today's most prevalent infectious diseases and even more.

How many of these diseases will we eradicate completely? The Pan American Health Organization has targeted measles as the next one for the Americas and has already made tremendous progress toward that goal. Given the problems encountered with polio eradication efforts in Africa and South Asia, global control of measles may be more realistic than total eradication. In principle, however, any microorganism against which there is a highly effective vaccine, which has no animal reservoir, and which (unlike tetanus and anthrax) does not persist long term in soil or water, is eradicable.

The two major challenges are cost and the fact that an organism against which infants are not being immunized because it has been eradicated, such as smallpox, could be used for bioterrorism. Short of eradication, it is encouraging to note how rapidly a disease can be brought under control. For example, in Taiwan the widespread use of hepatitis B vaccine has dramatically lowered the carrier rate and has already diminished the incidence of liver cancer in relevant cohorts.

A golden century?
In a world sobered by the events of Sept. 11, 2001, it is no longer naïve to hope that grave social inequities around the globe will finally receive the attention they deserve. There is growing recognition that a reservoir of communicable disease in any country represents a global threat, given the extent of international travel. Prevention of infection is not only better than cure, it is much cheaper.

Yet for the splendid examples of Rotary International and Bill and Melinda Gates to be followed more extensively, one additional realization is needed. That is the nexus between health and economic development. In the words of Harvard economist Jeffrey D. Sachs and his colleagues: "The linkages of health to poverty reduction and to long-term economic growth are powerful, much stronger than is generally understood. The burden of disease in some low-income regions stands as a stark barrier to economic growth."

Sachs estimates that $30 billion per year of additional donor support could save 8 million lives each year and provide direct economic benefits of $186 billion per year. Over the next 100 years, that adds up to truly astounding progress for the human race. As far as vaccines are concerned, the long journey from Edward Jenner to William H. Gates III would then have represented only the beginning of a golden era in public health.

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