News / Health

Researchers Warn Against TB Drug-Resistance

A patient who tested positive for extreme drug resistant tuberculosis awaits treatment at a rural hospital at Tugela Ferry in South Africa's impoverished KwaZulu Natal province, (File photo).
A patient who tested positive for extreme drug resistant tuberculosis awaits treatment at a rural hospital at Tugela Ferry in South Africa's impoverished KwaZulu Natal province, (File photo).
Jessica Berman
Studies show a short course of an inexpensive anti-tuberculosis drug can dramatically reduce transmission of the bacterial respiratory disease.  That's why many public health experts promote the use of the single antibiotic - called isoniazid - in communities with large populations of HIV-infected individuals -- people with notoriously high rates of secondary TB infections.  Researchers, however, caution that widespread use of isoniazid could speed the emergence of drug-resistant strains of TB. 

The World Health Organization recommends giving a six-month course of isoniazid preventive therapy (IPT) to three groups of people at risk of becoming infected with tuberculosis and spreading it to others.  Included were individuals infected with HIV, the virus that causes AIDS; children under the age of five with immature immune systems; and people who have been exposed to tuberculosis and test positive for the disease.

In studies using short course anti-TB therapy, results have been impressive, according to Mario Raviglione, director of the World Health Organization’s Stop-TB office.

Raviglione says IPT suppresses TB infection in 60 to 70 percent of HIV-negative individuals and 80 to 90 percent of those with HIV.

“You just don’t become infectious to others and [you] yourself are not affected by the disease,” he said.

Despite the demonstrated effectiveness of isoniazid preventative therapy, Raviglione says it’s rarely used.  He notes that IPT is limited to about 400,000 HIV-infected individuals, a fraction of the eight million people living with HIV globally who are at highest risk of becoming infected with TB.  And he says the single-drug therapy is almost never used in children or others exposed to TB.

But with an estimated one-third of the world’s population infected with a latent form of TB that could become active -- and lethal -- at any time, some international public health officials have proposed using isoniazid prophylaxis, or prevention, in entire at-risk communities throughout the developing world.

Others, like Caroline Colijn, think such widespread use of isoniazid mono-therapy to contain TB is potentially too risky.  

Colijn, of Imperial College London, and colleagues constructed a mathematical model that shows how blanketing a community with a single anti-TB drug, such as isoniazid in IPT, paves the way for the eventual emergence of drug-resistant strains of the TB bacterium.

“We don’t argue against doing IPT.  It’s probably one of the best interventions we have against TB," he noted. "But we would definitely argue that we need to consider these long-term consequences and roll out appropriate treatment for resistant TB and treatment for TB.”

The WHO’s Raviglione agrees, saying the key to a successful tuberculosis prevention strategy is making sure people who are actively infected with TB are not treated with a single drug.

“This mathematical model doesn’t change our concern because we knew if you are not doing a proper job in screening out, in ruling out, active tuberculosis when you start prophylaxis, then you run the concrete risk of developing drug resistance in that very person,” he explained.

An article describing the risks of promoting drug-resistant forms of tuberculosis with the widespread use of Isoniazid Preventive Therapy against TB appears in the journal Science Translational Medicine.

You May Like

EU Court Fines Poland for Hosting CIA 'Black Sites'

Ruling is first time a court has acknowledged suspects were held and tortured at the sites, under US program launched following the 9/11 terrorist attacks More

Migrant Issues Close to Home Spur Groups to Take Action

Groups placing water, food in the desert, or aiding detainees after release, have one common goal: no more deaths of migrants crossing illegally into the US More

Video At AIDS Conference, Prevention Pill Stirs Excitement

Truveda shows promise, spurring debate over access and other approaches More

Featured Videos

Your JavaScript is turned off or you have an old version of Adobe's Flash Player. Get the latest Flash player.
Israel Targets Gaza Supply Tunnelsi
X
July 24, 2014 4:42 AM
The Israeli military has launched a ground operation in Gaza to destroy the myriad tunnels that may have been used to smuggle weapons to Hamas. VOA's Zlatica Hoke reports that could mean more hardship for the people of Gaza, who obtain some of their essential supplies through these underground passages
Video

Video Israel Targets Gaza Supply Tunnels

The Israeli military has launched a ground operation in Gaza to destroy the myriad tunnels that may have been used to smuggle weapons to Hamas. VOA's Zlatica Hoke reports that could mean more hardship for the people of Gaza, who obtain some of their essential supplies through these underground passages
Video

Video MH17's 'Black Boxes' Could Reveal Crash Details

The government of Malaysia now has custody of the cockpit voice and flight data recorders from Malaysia Airlines Flight 17, which was hit by a missile over Ukraine before crashing last week. As VOA's Carolyn Presutti reports, the so-called black boxes may hold information about the final minutes of the flight.
Video

Video Living in the Shadows Panel Discussion

Following a screening of the new VOA documentary, "AIDS - Living in the Shadows," at the World AIDS conference in Melbourne, a panel discussed the film and how to combat the stigma associated with HIV/AIDS.
Video

Video IAEA: Iran Turns its Enriched Uranium Into Less Harmful Form

Iran has converted its stockpiles of enriched uranium into a less dangerous form that is more difficult to use for nuclear weapons, according to the United Nations’ Atomic Energy Agency. The move complies with an interim deal reached with Western powers on Iran's nuclear program last year, in exchange for easing of sanctions. Henry Ridgwell reports for VOA from London.
Video

Video Relic of Saint Draws Catholics Worried About Immigration Issue

A Roman Catholic saint who is a figure of devotion for those crossing the border into the United States is attracting believers concerned about the plight of undocumented immigrants. Mike O'Sullivan reports from Los Angeles, where a relic of Saint Toribio has drawn thousands to local churches.
Video

Video US Awards Medal of Honor for Heroics in Bloodiest of Afghan Battles

U.S. combat troops are withdrawing from Afghanistan, on pace to leave the country by the end of this year. But on Monday, U.S. President Barack Obama took time to honor a soldier whose actions while under fire in Afghanistan earned him the Medal of Honor. VOA's Jeff Seldin has more from the Pentagon.
Video

Video Ukraine Rebels Surrender MH17 Black Boxes

After days of negotiations, a senior separatist leader handed over two black boxes from an airliner downed over eastern Ukraine to Malaysian experts early Tuesday. While on Monday, the U.N. Security Council unanimously demanded that armed groups controlling the crash site allow safe and unrestricted access to the wreckage.
Video

Video In Cambodia, HIV Diagnosis Brings Deadly Shame

Although HIV/AIDS is now a treatable condition, a positive diagnosis is still a life altering experience. In Cambodia, people living with HIV are often disowned by friends, family and the community. This humiliation can be unbearable. We bring you one Cambodian woman’s struggle to overcome a life tragedy and her own HIV positive diagnosis.

AppleAndroid