News / Africa

In Cameroon, TB Vaccine Breakthrough Elusive

Tuberculosis vaccine breakthrough eludes researchers in Cameroon due to 'clever' nature of TB-causing bacteria



Deaths from tuberculosis are increasing in the developing world and especially in Africa.  It’s the world’s second deadliest infectious disease after HIV/AIDS.  In 2008, nearly two million people died of TB and researchers warn that mortality rates will surge further if new drugs and vaccines are not developed.

Linda is a 35-year-old Cameroonian mother of two.  She’s one of 35.000 people in the country diagnosed every year with tuberculosis, which kills some 7,000.  Her problem is compounded by the fact that she’s also infected with HIV, the virus that causes AIDS.

X-ray of patient with tuberculosis
X-ray of patient with tuberculosis

“It is very difficult,” she said. “Several times, I consider suicide but then I think about my children and want to be there for them.  I have had TB for several years and despite all the drugs, I am still ill.  The doctor says my problem is severe because I also have HIV.  I have to take countless numbers of medicines every day and sometimes I just can’t stand it.”

Like others in her condition, Linda longs for the day when an effective remedy will be found.

In early October, more than 200 researchers met for an international symposium in the Cameroonian capital, Yaounde.  They discussed the disease, but had no new drugs or vaccines to report.  They could only talk about new ways to improve existing treatments.

The meeting was hosted by the Novartis Institute for Tropical Diseases, a non-profit research organization trying to find new medicines for the treatment of neglected, infectious diseases like TB, malaria and Dengue fever.

One of the conference participants, Prof. Barry Clifton of the US National Institutes of Health, says the absence of new drugs is steadily increasing the number of deaths from TB:

“I don’t feel very optimistic about a breakthrough any time in the foreseeable future unless people put more effort and emphasis and research into tackling TB,” he said.  “At our current level, I think we’ll keep the pace to the point where we hopefully don’t have many people who don’t have any options.  But we’re not going to win the race.”

Paul Herrling in a discussion with symposium attendee
Paul Herrling in a discussion with symposium attendee

The only available vaccine for TB, known as Bacille-Calmette-Guerin (BCG) was developed almost 90 years ago.  It’s a live vaccine similar to the TB bacterium and has been improved over the years to provide immunity with the first dose.

But while it reduces risks of severe forms of TB in early childhood, it is not very effective in adults, who can be infected even if they were vaccinated in their youth. And BCG is not safe for children with HIV because it can spur the onset of the disease in those with weakened immune systems.  Across Africa, most children are given the vaccine without knowledge of their HIV status.

The link Between HIV and TB

Prof. Paul Herrling is head of the Novartis Institutes for Developing World Medical Research. He says there are a number of reasons for the current dilemma:

“The first one is that the last medicines that we had for TB are about 40 years old, and one thing that people did not know at that time is that this is a very clever bacterium and when they’re treated with the same medicines for a long time, they learn to escape it.  That’s what we call resistance,” he said.

Scientists say TB strains can vary from multi-drug resistant (MDR-TB) to extensively drug resistant (XDR-TB).

The most prominent way the TB virus gains resistance is in patients’ failing to complete their treatments.

Researchers say fighting tuberculosis is made more difficult by the increasing number of people, especially in Africa, like Linda, who are also infected with HIV.  Prof. Christopher Kuaban of the University of Yaounde in Cameroon says HIV/AIDS patients are up to 20 times more likely to develop TB than people without HIV:

“HIV is an infection that destroys your immune system. TB is contained by this immune system – so if your immune system breaks down when you’re infected by TB, the TB germ has nothing to fear because there’s nobody to destroy it. That’s why in any country where HIV is common, TB becomes very common,” he said.

Ongoing research inconclusive

Current treatment is cumbersome: it takes six to nine months and patients must take several tablets several times a day.  Research in several parts of the world is focusing on developing treatment that’s easier for the patient, as well as vaccines that may replace BCG.

Clinical trials are about to begin on one vaccine candidate - called AERAS-422.  They will be conducted in Kenya, South Africa, Uganda and India by the non-profit research organization Aeras Global TB Vaccine Foundation.  It recently obtained a $785,000 three-year-grant from the U.S. Food and Drug Administration.  Officials say the results may be available by the year 2020.

University of Yaounde (Cameroon) TB
University of Yaounde (Cameroon) TB

Funding is a problem say researchers like Barry Clifton:

“A normal pharmaceutical company will take a hundred people working for several years to get a candidate to put into clinical trials," he said. "With TB, we don’t have those kinds of resources because it’s a developing world disease, and there’s no financial incentive.  So, we try to do the best we can with the small resources we have.  It’s market-driven, so the big pharmaceutical companies are responsible for making money [for their shareholders].”

Meantime, the epidemic continues to grow, especially in Africa, where cities are increasingly crowded, where poor people find little to eat to bolster their immune systems, and where healthcare services are not adequate.

As a result, more and more people like Linda and her children are victims of stigma and discrimination. They are increasingly turning their backs on hospitals and heading for traditional healers and proliferating prayer churches for help.

TB’s intimidating complexities

TB is caused by a bacterium known as the Mycobacterium tuberculosis.  It’s spread from person to person through tiny airborne droplets of infected sputum.  It can affect almost any tissue or organ in the body, with the most common site being the lungs.  Basically, it cripples the human immune system, leaving patients vulnerable to deadly bacterial infection.

The WHO says of the nine million people diagnosed with TB worldwide last year, a third live in Africa.  It’s currently the leading cause of death among people with HIV/AIDS on the continent.

You May Like

Beijing Warns US on S. China Sea Patrols

Warning follows news reports Thursday that US military is planning to sail warships close to artificial islands Beijing has been aggressively building More

Indian PM Calls for Unity Amid Tense Climate Over Beef Attacks

Recent series of beef-related incidents seen as signs of rising intolerance toward Muslims and other religious minorities More

Why These Are New York City's Most Treasured Spaces

Under threat of jail time and fines, some New York property owners are not allowed to renovate their spaces without prior approval More

This forum has been closed.
There are no comments in this forum. Be first and add one

Featured Videos

Your JavaScript is turned off or you have an old version of Adobe's Flash Player. Get the latest Flash player.
House Republicans in Chaos as Speaker Favorite Withdrawsi
Jim Malone
October 09, 2015 12:32 AM
The Republican widely expected to become the next speaker of the House of Representatives shocked his colleagues Thursday by announcing he was withdrawing his candidacy. The decision by Majority Leader Kevin McCarthy means the race to succeed retiring Speaker John Boehner is now wide open. VOA National Correspondent Jim Malone reports.

Video House Republicans in Chaos as Speaker Favorite Withdraws

The Republican widely expected to become the next speaker of the House of Representatives shocked his colleagues Thursday by announcing he was withdrawing his candidacy. The decision by Majority Leader Kevin McCarthy means the race to succeed retiring Speaker John Boehner is now wide open. VOA National Correspondent Jim Malone reports.

Video German, US Officials Investigate Volkswagen

German officials have taken steps to restore some of the reputation their car industry has lost after a recent Volkswagen diesel emissions scandal. Authorities have searched Volkswagen headquarters and other locations in an effort to identify the culprits in the creation of software that helps cheat on emission tests. Meanwhile, a group of lawmakers in Washington held a hearing to get to the bottom of the cheating strategy that was first discovered in the United States. Zlatica Hoke reports.

Video Why Are Gun Laws So Hard for Congress to Tackle?

Since taking office, President Barack Obama has spoken out or issued statements about 15 mass shootings. The most recent shooting, in which 10 people were killed at a community college, sparked outrage over the nation's gun laws. But changing those laws isn't as easy as many think. VOA's Carolyn Presutti reports.

Video Hungary Criticized for Handling of Refugees

Amnesty International has accused Hungary of breaking multiple international and European human rights laws in its handling of the refugee crisis. As Henry Ridgwell reports, thousands of migrants and refugees continue to travel through the Balkans to Hungary every day.

Video Iraqi-Kurdish Teachers Vow to Continue Protest

Sixteen people were injured when police used tear gas and rubber bullets to disperse teachers and other public employees who took to the streets in Iraq’s Kurdish north, demanding their salaries from the Kurdish Regional Government (KRG). VOA’s Dilshad Anwar, in Sulaimaniya, caught up with protesting teachers who say they have not been paid for three months. Parke Brewer narrates his report.

Video Syrian Village Community Faces Double Displacement in Lebanon

Driven by war from their village in southwestern Syria, a group of families found shelter in Lebanon, resettling en masse in a half-built university to form one of the biggest settlements of its kind in Lebanon. Three years later, however, they now face being kicked out and dispersed in a country where finding shelter as a refugee can be especially tough. John Owens has more for VOA from the city of Saida, also known as Sidon.

Video Bat Colony: Unusual Tourist Attraction in Texas

The action hero Batman might be everyone’s favorite but real bats hardly get that kind of adoration. Put more than a million of these creatures of the night together and it only evokes images of horror. Sarah Zaman visited the largest urban bat colony in North America to see just how well bat and human get along with each other.

Video Device Shows Promise of Stopping Motion Sickness

It’s a sickening feeling — the dizziness, nausea and vomiting that comes with motion sickness. But a device now being developed could stop motion sickness by suppressing certain signals in the brain. VOA’s Deborah Block reports.

Video Making a Mint

While apples, corn, and cranberries top the list of fall produce in the US, it’s also the time to harvest gum, candy, and toothpaste—or at least the oil that makes them minty fresh. Erika Celeste reports from South Bend, Indiana on the mint harvest.

Video Activists Decry Lagos Slum Demolition

Acting on a court order, authorities in Nigeria demolished a slum last month in the commercial capital, Lagos. But human rights activists say the order was illegal, and the community was razed to make way for a government housing project. Chris Stein has more from Lagos.

Video TPP Agreed, But Faces Stiff Opposition

President Barack Obama promoted the Trans-Pacific Partnership on Tuesday, one day after 12 Pacific Rim nations reached the free trade deal in Atlanta. The controversial pact that would involve about 40 percent of global trade still needs approval by lawmakers in respective countries. Zlatica Hoke reports Obama is facing strong opposition to the deal, including from members of his own party.

Video Ukranian Artist Portrays Putin in an Unusual Way

As Russian President Vladimir Putin was addressing the United Nations in New York last month, he was also being featured in an art exhibition in Washington. It’s not a flattering exhibit. It’s done by a Ukrainian artist in a unique medium. And its creator says it’s not only a work of art - it’s a political statement. VOA’s Tetiana Kharchenko has more.

VOA Blogs