WIKIMEDIA COMMONS, CDC PUBLIC HEALTH IMAGE LIBRARY
Thousands of children, women, and men die each day from tuberculosis (TB). It is the deadliest infectious disease after HIV, and increasing drug resistance threatens to wipe out medicine’s best weapons against the TB bacterium. New tools to control the disease are needed to bring this global epidemic to a halt and prevent millions from suffering. To this end, we and others drafted “Tuberculosis Vaccines: A Strategic Blueprint for the Next Decade,” which lays out a plan for solving the current problems caused by this ancient disease using one of the most effective and affordable public health tools modern science offers for infectious diseases: vaccines.
The only vaccine currently available for TB was developed more than 90 years ago and is ineffective against the spread of disease, serving only to prevent cases of TB in young children. New vaccines that can prevent the progression of disease in adult populations are desperately needed; despite mostly effective treatment programs, tuberculosis continues to spread with nearly 9 million new cases each year. New vaccines are also required to prevent the transmission of drug resistant TB strains, a significant problem in both developed and developing countries.
Fortunately, such vaccines are on their way. While a decade ago, no new vaccines for TB had progressed to clinical trials, today 12 novel vaccine constructs are in various stages of testing their safety and efficacy in people. In the next 2 to 3 years, we will find out if two of these vaccines will be effective in certain populations at risk for TB. This is a pivotal moment. If these trials are successful, the TB community needs to be ready and prepared to move forward rapidly into large multi-country clinical studies to show that the vaccines are safe and effective enough to be licensed and used in the countries that need them the most. Alternatively, if the current trials are unsuccessful we need to be prepared with a backup plan consisting of vaccine candidates that work by different mechanisms. These vaccines should be effective in all target populations, including the estimated 2 billion latently infected people—a formidable, largely uncontrolled reservoir for development of new TB cases, particularly in individuals co-infected with HIV.
The Blueprint, created under the guidance of the Stop TB Partnership Working Group on New Vaccines and published this March in the journal Tuberculosis, provides a detailed plan for developing and introducing TB vaccines over the next decade. It identifies five key areas where efforts should be prioritized to successfully advance TB vaccines around the world. First, important research questions need to be addressed. Will the vaccines work in all populations and against drug-resistant strains of the bacterium? Can vaccines prevent against the initial lung infection as well as against progression of disease? Second, we need to know how vaccines will work and why some people are resistant to TB and never become sick. Finding the answer to this question will help us build better vaccines. Third, we need to think globally and act locally in the design of clinical trials. We need to design clinical studies that will prove that the vaccines will work in all populations, including those suffering from HIV and those in developing countries. Fourth, specific criteria need to be objectively agreed upon so that the best vaccines can move forward with the least delay. Finally, in today’s economic climate, we need creative mechanisms to raise awareness of the global problem of TB and finance the objectives of the Blueprint. If the Blueprint is an engineering plan for building our house with five rooms, we now need the builders to come forward with their financing and the workers to bring their bag of tools.
With one and a half million people dying each year from TB, one third of the world’s population infected with TB, and drug-resistant strains of TB on the rise, we can no longer sit patiently and wait for the slow development of effective vaccines. There is urgency to our plan and a need for scientists, health officials, national decision makers, and leaders of the communities most affected by this disease to demand that the actions outlined in the Blueprint be supported. With the progress of the last decade and an acceleration of our efforts, individuals may benefit from a new TB vaccine as soon as the end of this decade.
Jelle Thole is the founder and director of the TuBerculosis Vaccine Initiative (TBVI), an international not-for-profit foundation based in The Netherlands that aims to develop new vaccines against human tuberculosis. Michael Brennan is the senior advisor for Global Affairs at Aeras, a non-profit product development organization dedicated to TB vaccine development.