New TB Vaccine Enters Clinical Trials
It has been nearly 90 years since the currently available TB (tuberculosis) vaccine was invented, and a new TB vaccine is long overdue. Aeras Global TB Vaccine Foundation has announced it will begin a clinical trial of an investigational TB vaccine that will hopefully stop all stages of infection.
New TB Vaccine Needed to Replace BCG Vaccine
TB is a contagious disease caused by a bacterium called Mycobacterium tuberculosis. The bacteria mostly attack the lungs (pulmonary TB), but they can also attack the spine, brain, and kidneys. If not treated properly, TB can be fatal. The World Health Organization (WHO) estimated 8.9 to 9.9 million incident cases of TB in 2008, and 1.5 to 2.3 million deaths among both HIV-negative and HIV-positive individuals.
The currently used TB vaccine, Bacille Calmette Guerin (BCG), can reduce the risk of severe TB in young children but it is not very effective in preventing pulmonary TB in adolescents and adults, which are the populations with the highest rates of the disease.
People who are infected with TB germs, called bacilli, do not necessarily become sick with the disease, but they can infect other people. WHO reports that someone in the world is newly infected with TB bacilli every second, and that one-third of the world’s population is infected with TB bacillus. The Centers for Disease Control and Prevention reported 12,898 cases of TB in the United States in 2008.
The new live recombinant vaccine, AERAS-422, will enter clinical trials led by researchers at Saint Louis University’s Center for Vaccine Development in Missouri. It will be evaluated for its ability to interrupt the disease at all stages of infection, including dormant periods and reactivation.
Participants in the trial will include healthy adults who have never received a TB vaccination. The investigative team, which will be led by Daniel Hoft, MD, PhD, will also perform initial immunological evaluations.
According to Thomas G. Evans, MD, Aeras’ chief scientific officer, “we are cautiously optimistic about the potential of this vaccine candidate to be safer and more immunogenic than the currently available vaccine.” This vaccine is part of a worldwide effort to develop vaccines that are effective against all types of TB.
Although TB is no longer an epidemic in the United States or many other developed countries, it continues to be so in other places, especially South Africa, where there is much resistance to TB treatments.
Scientists involved with the clinical trials of the new TB vaccine note that these efforts are important not only because it may result in a more effective TB vaccine, but “it is also an opportunity to learn more about cellular immunity, a less well understood but critically important component of TB vaccine development.”
Aeras Global TB Vaccine Foundation
Centers for Disease Control and Prevention
World Health Organization