With cases of drug resistant tuberculosis (TB) on the rise globally, top TB researchers at a briefing today in London, called for greater focus on the quest for new vaccines—a crucial cost-effective method for addressing the growing threat. The WHO estimates that 9% cases of multidrug-resistant (MDR) TB in fact have extensively drug-resistant (XDR) TB for which even fewer drugs are effective, and a recent research published in The Lancet in August suggests that levels of drug-resistant TB are higher than previously appreciated and rates of XDR-TB range from 0.8-15.2% of MDR-TB cases at study sites across the world.
The event at the Science Media Centre was addressed by Professor Helen McShane from University of Oxford, Dr Ann Ginsberg, Vice President of Scientific Affairs at Aeras and Professor Tim McHugh from University College London. The three scientists are working on the frontlines of efforts of developing an effective vaccine to combat the disease, which remains the world’s second leading infectious killer taking an estimated 1.45 million lives in 2010.
“Vaccines are the ultimate long-term, cost-effective solution for addressing tuberculosis. It is important that we continue to develop better drugs and diagnostics to help us rapidly diagnose TB and identify drug-resistant strains, but we must invest in vaccine research now if our ultimate goal is to be able to prevent the disease rather than forever chase growing drug resistance with new drugs,” said Professor Helen McShane.
Once known as “consumption” for the slow wasting away of people who die from it, tuberculosis is one of history’s great global killers. One out of every three people globally is thought to be latently infected by the airborne TB organism, although a much smaller number will go on to develop the disease. More than half of all reported TB cases are from Asia-- most of them in India, Pakistan, China and Indonesia. South Africa, which has the highest rate in Africa, accounts for 26% of the burden of the disease globally. In 2011, the incidence rate in the UK rose 6.6% over the previous year. London has been dubbed the TB Capital of Western Europe as it is home to nearly 40% of all TB patients in the UK.
“Vaccines that prevent adolescents and adults from developing infectious tuberculosis would be the single greatest advance in the global fight against the disease,” said Dr Ginsberg. “Much of the most exciting TB vaccine discovery work is happening in the United Kingdom and Europe with significant support from the UK government.”
During the last decade, TB vaccine research has made dramatic strides with the number of TB vaccines in clinical trials growing from zero to more than 12. MVA85A, the vaccine developed in Professor McShane’s laboratory, is the most clinically-advanced TB vaccine candidate in the world. The first efficacy results are expected early next year based on the outcome of a clinical trial in South Africa, carried out at the South African Tuberculosis Vaccine Initiative with support from Aeras, The Wellcome Trust, the European Commission, Emergent Bio Solutions and the Oxford-Emergent Tuberculosis Consortium.
Another cause for worry is that globally anti TB drug resistance has grown chiefly because of misuse of anti-TB drugs; poor management of the disease and transmission of drug-resistant strains from person to person. In the UK itself the total number of cases of drug-resistant TB has risen by more than 50% in the last decade.
Professor McHugh cautioned that treatment for MDR-TB is more expensive than for drug-susceptible TB, and is protracted lasting up to two years, the drugs used have significant side effects and in many settings clinicians are unable to diagnose MDR-TB rapidly, increasing the risk of patients spreading the drug resistant strains while receiving treatment that may be ineffective against the infection. He said that, “The development of new treatments and diagnostics are vital for treatment of individuals infected with drug-resistant strains of TB. But drugs alone will not control the spread of TB and investments in vaccines are essential to protect the wider community.”
Citizen News Service (CNS)
