The study found that the immunisation reduced the rate of definite tuberculosis by 39 percent among 2,000 HIV-infected patients in Tanzania. "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 of the study," said principal investigator Ford von Reyn.
The seven-year, randomised, placebo-controlled trial was conducted in Tanzania. The group began Phase-I human studies in the United States in 1994, and demonstrated that a multiple-dose series of the vaccine was safe in both healthy subjects and patients with HIV infection.
The group then conducted Phase-II studies in larger groups of adults in Zambia and in Finland. In the Zambian trial, researchers found that the vaccine boosted immune responses against tuberculosis that had first been primed in childhood with the current TB vaccine, BCG.
Subsequently the group conducted the Phase-III efficacy trial among HIV-infected patients with prior BCG immunisation in Tanzania. 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. He added that the next steps are to improve the manufacturing methods to support the production of the larger quantities of the TB vaccine needed for further studies and subsequent clinical use. The vaccine is a type known as an inactivated, whole-cell mycobacterial vaccine and is expected to be economical to produce and distribute, von Reyn said.
MEDICA.de; Source: Dartmouth College