The global status of MDR- and XDR- tuberculosis (TB) infection is considered a public health crisis. The United Nations 2000 goal was to stop and reverse the incidence of TB by
- Extending patient access to diagnosis and treatment and
- Expanding the directly observed treatment short course (DOTS) program, monitored by the World Health Organization (WHO), around the world to stop drug-sensitive TB
However, deterring drug-resistant infection (MDR- and XDR-TB) requires a greater effort to improve healthcare facilities, create new diagnostic methods, and develop new anti-TB drugs, particularly vaccines. Although testing with the Xpert® (Cepheid) is rapid and specific for MTB/rifampin (RIF) resistance, the cost is prohibitive in certain developing countries; pharmaceutical companies are reluctant to support new antimicrobial products they expect will not be lucrative. Vaccine development remains the only hope of eradicating selective antimicrobial resistance, which has precipitated the transmission of quasi-incurable strains of MTB, such as TDR-TB.
The TB Vaccine Initiative in 2008, funded by European countries, non-governmental organizations, and private individuals, has supported the research behind MVA85A, the most advanced vaccine product known. The mechanism involves a virus used to activate the immune system’s T cells, previously primed by BCG. In a phase II clinical trial that started in 2009 in South Africa, 3,000 babies vaccinated with BCG, as well as a group of HIV-infected adults, were tested through the efforts of researcher Helen McShane, PhD, at the University of Oxford, UK. Unfortunately, the expected cost of $8 billion per year for treatment and control of TB (by 2015) creates another hurdle. The XXDR-TB or presumed TDR-TB epidemic in Mumbai, India, adding to earlier reports of similar untreatable strains from Iran and Italy has elevated this crisis to another level, one which we can no longer afford to ignore. As of 2016, there were clinical trials in progress for at least 12 new TB vaccines.