The HIV Vaccine
Unlike all the other vaccines discussed in this book, the HIV vaccine is unique because no safe and efficacious vaccine has been developed yet. While there are several experimental versions of the HIV vaccine under investigation, none of them have been proven to be effective so far. In previous clinical trials, the investigational HIV vaccines failed to protect recipients from HIV infection.
Acquired immune deficiency syndrome (AIDS) is the infection caused by the human immunodeficiency virus (HIV). The virus directly attacks particular types of immune cells in the body. While HIV does not usually kill its victim directly, the virus decimates the body's defense against other germs, and other infections (such as parasites, tuberculosis, and fungi) take the opportunity to invade defenseless victims and claim the lives of AIDS patients.
The difference between HIV infection and AIDS is that people who are infected with HIV are not diagnosed with AIDS until their immune system has been weakened severely to the point that they become susceptible to many infections. The speed of which the immune system deteriorates depends on a variety of factors — age of the patient, route of transmission, nutritional status, and additional unknown factors. It may take 10 years or more before a person with HIV comes down with AIDS.
In 2008, the French scientist Luc Montagnier won the Nobel Prize in Medicine for discovering the human immunodeficiency virus and ascertaining its role in causing AIDS. The American researcher Robert Gallo initially claimed that he independently discovered the virus, but it was later found that the virus in Gallo's laboratory was the same one from the French lab.
You may associate HIV infection with certain groups of people — homosexual men and intravenous drug users — but the AIDS global epidemic reveals a different picture. The HIV infection rate in the United States and most developed countries is on the decline, and the vast majority of new infections now occur in Africa. No one is immune to the infection. Heterosexual transmission is most common. AIDS wipes out entire families and villages, frequently leaving helpless orphans behind who are also HIV positive.
HIV infection can be transmitted through unprotected sexual intercourse, breast-feeding, and from the infected mother to her baby during birth. Intravenous drug use is another common way for the virus to spread. Some patients who receive frequent blood transfusions have been infected through contaminated blood in blood banks, but that rarely occurs now since blood donors are carefully screened for the HIV infection.
Many people falsely believe that AIDS can be successfully treated with a combination of antiviral medications. While it is feasible to halt the progression of the infection, it is impossible to eradicate the virus completely from the body.
Since the HIV infection is incurable, the best strategy to combat this global epidemic is through preventive vaccination. Prevention via safe sex practices has failed miserably to curb new infections around the world, especially in developing countries. Since the 1980s, about 25 million people have died from AIDS, and the epidemic continues to claim the lives of millions of people each year.
The HIV vaccine was at one point the shining light in the battle with HIV. However, the effort to produce an effective and safe vaccine in the past twenty years has yielded few results, despite an international collaboration in this pursuit. While there are new vaccines that are in the planning stages, it is unlikely that there will be a working vaccine in the near future.
The difficulty with making a working HIV vaccine lies in the fact that the HIV changes constantly. In addition, there are so many subtypes of the virus that a single vaccine cannot possibly protect against so many different variants of the virus. The greatest obstacle yet is to find out how the human body defends itself from the HIV infection. So far, scientists cannot find a reliable mechanism for the immune system to ward off the HIV infection. All previous attempts at coming up with a vaccine have failed miserably.
In the summer of 2009, a scientific team from the Scripps Research Institute in California announced that they discovered neutralizing antibodies against the virus causing AIDS. This could potentially be the first crucial step in paving the way to developing a vaccine that prevents the HIV infection.
It is possible that scientists may not be able to develop an HIV vaccine for a long time to come. In the mean time, the best strategy against the infection rests on prevention. Condom use is only effective in protecting HIV infection 85 percent of the time, so abstinence is the only way to avoid the infection.