TB is the biggest killer of those afflicted by HIV
infection because of weaker immunity. MV works by enhancing the vulnerable responses of patients who have been inoculated with the BCG vaccine which offers some protection against the disease.
Principal Investigator Dr. Ford von Reyn described the trial as a "significant milestone -- the first to demonstrate that any type of vaccine can prevent an infectious complication of HIV in adults".
Trials conducted in three phases
The researchers from Dartmouth Medical School in the U.S. tested MV among HIV positive patients in three phases over a period of seven years.
They began Phase-I in the United States in 1994 and found that a multiple-dose series of MV was safe in both healthy subjects and patients with HIV infection.
The scientists then carried out a larger study in adults of Zambia and Finland in the Phase-II. They noted that MV helped the immunity response against TB in those who had been given the BCG shot in childhood.
The vaccine was then tested in a large Phase-III efficacy trial among 2,000 HIV outpatients in Tanzania. The patients were tracked every three months for an average of 3.3 years.
The researchers observed that the experimental vaccine MV lowered the rate of definite TB by 39 percent among HIV-infected patients.
"Since development of a new vaccine against tuberculosis is a major international health priority, especially for patients with HIV infection, we and our Tanzanian collaborators are very encouraged by the results," said von Reyn.
The next course of action
The researchers are now speculating the procedure of administrating MV before the start of antiretroviral drugs because the newly-infected HIV patients are more vulnerable and contract TB almost immediately.
The next step would be to improve the manufacturing methods to produce larger amounts of the vaccine for further research and later for clinical use, if approved by regulators.
Alvaro Bermejo, executive director at the International HIV/AIDS Alliance, said, "This is a very important finding - it is the first time we are going to have a vaccine which is influential in preventing opportunistic infections in HIV patients.
"TB is a massive problem - a third of people living with HIV in Africa are infected with it. The reduction of 39% seen in Tanzania, although not fabulous, is a good result."
The study was sponsored by the U.S. National Institutes of Health and appears in the latest online issue of the Journal AIDS, and it will be published in the March print issue of AIDS.
Post new comment