A seven-year clinical trial in Tanzania has shown that a new vaccine can reduce by nearly 40% the likelihood of people with HIV contracting tuberculosis.

Results from the DarDar Health Study were reported by a research team from Dartmouth Medical School (DMS) in the US in the latest online issue of the journal AIDS. The study name also reflects the involvement of Muhimbili University of Health and Allied Sciences (MUHAS) in Dar es Salam, Tanzania.

Tuberculosis (TB) is the most common cause of death from HIV infection in developing countries and newly infected patients risk contracting TB “almost immediately”, noted Dartmouth College. Accordingly, the DMS investigators are looking at a strategy for immunisation with the Mycobacterium vaccae (MV) vaccine before patients need to start taking antiretroviral drugs for HIV.

MV is an inactivated, whole-cell mycobacterial vaccine that is expected to be economical to produce and distribute. Principal investigator Dr Ford von Reyn, director of the DarDar International Programs for the Section on Infectious Disease and International Health at DMS, described the DarDar study as a “significant milestone”, the first to demonstrate that any type of vaccine can prevent an infectious complication of HIV in adults.

In the randomised, placebo-controlled trial supported by a grant from the US National Institute of Allergy and Infectious Diseases, immunisation with MV reduced the rate of definitive tuberculosis by 39% among 2,000 HIV-infected patients in Tanzania.

The next step, von Reyn said, would be to improve manufacturing methods so that larger quantities of MV could be produced for further studies and subsequent clinical use. Development work will be undertaken by the Aeras Global TB Vaccine Foundation in Rockville, US in conjunction with UK-based manufacturer Immodulon Therapeutics.