Derived from the works of Paul-Henri Lambert, Tony Hawkridge, Willem A. Hanekom
Clinics in Chest Medicine, 2009, vol 3. (4) pp. 811-26
photo: Jad Davenport
Only one vaccine against tuberculosis (TB) now exists, bacille Calmette Guérin (BCG), which confers incomplete protection against the disease. BCG has shown a certain amount of success against childhood TB meningitis and military TB, but it has shown little to no efficacy against adult pulmonary TB and even goes so far as to cause disease in HIV infected infants. Despite widespread TB vaccination with BCG, 9.3 million people develop TB each year, with 1.8 million people dying from the disease, a large portion of which suffer from TB-HIV co-infection. Clearly, we need a new vaccine, one which better protects against lung disease, to control TB around the world.
Fortunately, important research in the development of new vaccines against tuberculosis is underway. A successful new vaccination strategy must significantly improve upon BCG, as well as having a noticeable effect on the global TB burden. Due to the extent of co-infection, the ultimate goal of these efforts is development of a vaccine safe for HIV infected infants.
Several different types of vaccines are under development. Live mycobacterial vaccines, based either on an improvement of BCG or an attenuation of M. tuberculosis, are in development in the United States (UCLA) and in Europe (Statens Serum Institute) with several options already in phase 1 clinical trials. Subunit and live vector-based vaccines are in development by AERAS, with several phase 1 trials ongoing since 2007 and with plans for phase 2b trials beginning in 2009.
A different approach is the development of therapeutic vaccines, which would accelerate or complement the effects of chemotherapy against TB. Three major randomized, placebo-controlled and partially blinded trials have taken place in Africa with positive results but with major geographic differences.
Despite the fact that TB drugs and a vaccine exist, the disease still remains a major cause of death around the world. Without improved tools, including a new vaccine, to fight TB, it will continue to devastate developing countries worldwide. Significant progress is being made, with several vaccines in phase 1 and 2b clinical trials. With more and more resources going towards the development of new vaccines and new TB drugs, we can hope for a better future.
What is your take on vaccination development? What are some other TB prevention and control strategies?