How HIV experts may be able to help crack the code and find SA's missing TB patients.
COMMENT
If a new disease epidemic killed 1.5 million people in one year, it would be covered extensively in the news, and all avenues to bring it to an end would likely be explored and funded.
But what about an existing disease that kills that many people? According to the World Health Organisation (WHO), tuberculosis (TB) killed 1.5-million people in 2014, causing more deaths than any other single infectious agent. The response to TB has been woefully inadequate to curb the epidemic.
South Africa’s health minister, Aaron Motsoaledi, recently said: “It is time for the world to treat tuberculosis with the same urgency it demonstrated in responding to major new health threats like Ebola and the Zika virus”.
Disease costs
Responding to the TB epidemic currently costs the world $8-billion a year, according to the WHO. But, according to a 2014 paper published in the journal, Proceedings of the National Academy of Science, it would only take a fraction of that to develop a new, cost-effective TB vaccine.
Unfortunately, current funding levels to support TB research and development are not sufficient to adequately advance the necessary science, partly because of the misconception that TB is a disease of the past and is easily treatable.
With existing treatments, TB’s human toll is tremendous, with approximately 9.6-million people developing active TB in 2014. This toll falls disproportionately on the developing world. South Africa has one of the highest incidences of TB in the world and, according to Statistics South Africa, has been the country’s leading cause of death since 1997.
An urgent threat
As strains of TB resistant to the most commonly used TB drugs have developed and spread, the threat of it is becoming more complex and urgent to address. People with multidrug-resistant (MDR) or extensively drug-resistant (XDR) TB require long courses of therapy with extremely expensive drugs that often are not well tolerated.
Although government figures show that MDR- and XDR-TB make up less than 2% of the total cases of TB in South Africa, it takes one-third of the nation’s total TB budget to provide treatment to these patients, according to the health charity, Global Health Education.
People with suppressed immunity, such as those living with HIV, are more likely to develop active TB. This is a particular issue for South Africa, where health department statistics reveal that two-thirds of patients with TB are also HIV-infected.
Programmes to control TB currently focus on early diagnosis and treatment and on the vaccination of infants with BCG. But BCG is simply not an effective enough vaccine to control the epidemic. It was first used nearly 100 years ago and is now the most widely used vaccine in the world.
Although BCG protects young children from the more severe forms of TB, it does not have an impact on the most common form of TB, pulmonary (lung) TB, in adolescents and adults. Research studies have shown that this is the age group most likely to develop and transmit TB, so a new vaccine to protect this population would be the single most important tool in controlling the epidemic.
Vaccines and prevention
Effective vaccines are the cornerstone of infectious disease prevention and there are many examples of serious infectious diseases that have been eradicated or controlled by effective vaccines, including smallpox, polio, diphtheria, tetanus and measles.
We also urgently need faster and more effective diagnostics so people can be put on treatment before they infect others, and shorter, safer courses of treatment to more effectively treat TB, including MDR- and XDR-TB.
The WHO has made clear that its goal to end the global TB epidemic by 2035 is not possible without these new tools. Delaying their development will result in millions of more cases of TB and will cost too many lives.
Dereck Tait is the senior clinical director and office lead for Aeras Africa