|MadSci Network: Immunology|
Dear Maja, You are absolutely correct that the combination of vaccines, good sanitation, personal hygiene, and drugs should be very effective in preventing morbidity and mortality from many infectious diseases. There are several reasons for this unfortunate situation, some scientific but others political and economic. I am most qualified to discuss the first of these and will comment briefly on the others. Vaccines are not yet available for some of the most devastating infectious diseases, AIDS being a prime example. Although there has been a lot of research in this area, and even some clinical trials of candidate vaccines, none have been very promising. HIV, the cause of AIDS, is a very crafty virus that can incapacitate the immune system. This makes developing a virus vaccine a real challenge. Many of the infectious diseases you are thinking about are more of a threat in developing rather than industrialized nations. There are some vaccines that require, for example, refrigeration to maintain activity and/or multiple immunizations for effective immunity. Both of these requirements are problematic in the developing world. Consistent refrigeration is not always available and there is often no established health care system in place so that patients can be followed up for re- vaccination. Some of these vaccines are expensive and this can also be prohibitive. Finally, sanitation may not be optimal. Cost unfortunately becomes an issue with drugs as well. For example, a combination of drugs called “Highly active antiretroviral therapy” (HAART) has significantly prolonged the lifespan and quality of life of AIDS patients. However these drugs are very expensive. Some effort has been made to get them into developing countries where HIV infection is rampant, but success has been less than it should be. Even when there is a cheap and relatively effective vaccine there are sometimes political/religious issues that prevent its widespread use. As you may know, there is currently a worldwide effort underway to eliminate polio. There have been recent problems in parts of Nigeria, where vaccination has been suspended because of unfounded fears that polio vaccine is contaminated with HIV, cancer causing compounds, or anti- fertility agents. So, there are many problems left to solve, only some of which can be solved by scientists. I do not want to paint too bleak a picture though, because despite all these temporary impediments there has been great progress in eliminating the threat of infectious diseases throughout the world.
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