Vaccination Helped Control Simian AIDS Virus for a Full Year
Dr. Picker believes that a vaccine for people may be available in three years.
The problem in stopping the spread of AIDS has always been that there are so many different ways that HIV can enter the human body. It is spread by heterosexual and homosexual sex acts. It is spread by shared needles and in rare instances by shared toothbrushes and razors. It can be transferred through breast milk and during the newborn's passage through the birth canal.
A vaccine for AIDS has to be able to counteract the virus no matter when or where it enters the body. Dr. Picker believes that his team has come up with a way to do just that.
Nearly everyone has been infected with a different virus known as CMV, or cytomegalovirus. Once an individual has survived infection with this virus, the immune system is constantly on alert to stop a new infection. The Oregon research team has modified CMV so that it can carry the vaccine for HIV. The immune system immediately recognizes the cytomegalovirus and is immediately activated by the vaccine to stop HIV.
"The virus comes in and can be basically stopped in its tracks," Dr. Picker told Reuter's Health.
Over the last 15 years, the survivability of AIDS infections has greatly increased. AIDS patients who take a cocktail of drugs often lead relatively symptom-free lives for decades, but their bodies are not able to get rid of the virus "lurking" in the immune system itself. The hope is that the vaccine may trigger changes in the immune system that eventually get rid of the AIDS virus altogether.
A study conducted in Thailand with 16,000 volunteers found that a different AIDS vaccine could prevent HIV infection in a small number of people, but this earlier vaccine showed no potential for strengthening the immune system so that it could get rid of the virus once infection had already occurred. Since the new vaccine relies on the ability of the immune system to do constant surveillance for cytomegalovirus, scientists hope that it will destroy the targeted HIV virus over a period of months or years.
Over 38,000,000 people are infected with HIV. Over 25,000,000 people have died of AIDS, especially in sub-Saharan Africa. HIV infection is spreading quickly, however, in India, Indonesia, and Pakistan, although it is on the wane in North America and much of Europe.
The challenge lying ahead for the vaccine scientists is to ensure that they choose a strain of CMV that will not cause its own symptoms, and that their findings in research with monkeys translate to human physiology. The next area of concern is to make sure that new vaccine itself does not cause lasting health problems.