The results of the first early test of a new type of tuberculosis vaccine show that it elicits strong immune responses in adults with or without a previous bacille Calmette-Guerin (BCG) vaccination.

Dr. Helen McShane, from the Centre for Clinical Vaccinology and Tropical Medicine at the University of Oxford in the UK, and colleagues report the study results in the journal Nature Medicine.

The vaccine (MVA85A) - a genetically engineered vaccinia virus that expresses a prominent TB protein - induced “high levels” of TB-specific immune cells when given to healthy adults who have never had a BCG vaccination, the researchers report.

“When we give MVA85A to people who have previously received BCG, the immune responses are stronger and last for at least 6 months after vaccination,” McShane told Reuters Health.

These initial results show that MVA85A is “safe and stimulates a strong cellular immune response,” McShane said.

“The next step is to see whether this improved immune response actually protects against disease,” she added, noting that the vaccine is already in clinical trials in Gambia and will enter trials in South Africa next year.

A booster MVA85A vaccination could offer a practical and efficient way to enhance and prolong anti-TB immunity in areas of the world were the disease is endemic, the investigators note in their paper.

SOURCE: Nature Medicine, for November, posted online October 24, 2004.