By Deena Beasley and Julie Steenhuysen
Reuters
Los Angeles county health officials have asked for federal assistance to analyze and contain an outbreak of tuberculosis within the city's homeless population, a spokeswoman for the county agency said on Friday. 

Los Angeles County Health Department spokeswoman Mabel Aragon said the agency is still in the process of confirming the number and type of TB cases in the county.

"The CDC is helping us with surveillance and statistic gathering," she said.

CDC spokesman Scott Bryan confirmed that the federal health agency has been asked by local and state TB officials to assist with the outbreak investigation. Bryan said the CDC plans to dispatch staff to the state in the next two weeks.

The Los Angeles Times reported that health workers have identified about 4,650 people who were probably exposed to a persistent outbreak of the contagious disease on downtown Los Angeles' skid row.

The newspaper said that over the past five years, county officials have identified 78 cases of a unique strain of the contagious disease, including 11 deaths. Sixty of those cases were homeless individuals leaving in the skid row area.

In an interview posted on the Los Angeles health department's website, Kiren Mitruka of the U.S. Centers for Disease Control and Prevention said: "Although progress has been made toward eliminating TB in the U.S., TB outbreaks continue to occur and remain a challenging issue."

The United States had about 10,528 cases of tuberculosis in 2011 and there were 529 deaths from the disease in 2009, according to the latest full year CDC statistics.

The CDC responds to TB outbreaks only when state and public health departments exceed their surge capacity to control it, Mitruka said.

"We don't go in unless we're asked," she said in the online interview.

Typically, the CDC will conduct an onsite investigation lasting two to three weeks, working closely with state and local public health partners, Mitruka added.

The cluster of TB cases going on in Los Angeles follows a pattern of infection. A review of 51 TB cases which the CDC investigated between 2002 and 2008 published in Emerging Infectious Diseases found substance abuse was the most common risk factor, with 58 percent of outbreak patients reporting substance abuse.

Tuberculosis infection destroys lung tissue, causing patients to cough up the bacteria which then spreads through the air and can be inhaled by others.

Most cases can be cured with a six-month cocktail of antibiotics, but rates of drug-resistant TB have been spreading fast, causing alarm among public health officials and prompting calls for more research into new treatments.

"I think it's a wake up call that highlights the fact that this is still a major, major problem," said Dr. Mel Spigelman, chief executive of the TB Alliance, a non-profit research group based in New York.

"Even in the U.S., where we have one of the lowest rates in the world, we still have over 10,000 patients every year who get TB."

Spigelman said that number pales in comparison to the 9 million people globally who get TB.

"It's still in the U.S., we just don't recognize it." 

The world's most advanced tuberculosis vaccine failed to protect babies against the infectious disease, according to a new study in South Africa.

The vaccine, MVA85A, was designed to improve protection from the only existing tuberculosis vaccine, BCG, which is routinely given to newborns. Though the new vaccine appeared safe, scientists found no proof it prevented tuberculosis, an airborne disease that kills more than 1 million people worldwide every year.

Previous tests of the vaccine in adults had been promising and researchers said the trial provided useful data to inform future studies. There are a dozen other TB vaccines currently being tested.

Some health officials were discouraged by the results. "It's pretty disappointing," said Dr. Jennifer Cohn, a medical coordinator at Doctors Without Borders, who was not part of the study. "Infants are at really high risk of TB but this doesn't seem to offer them any protection."

MVA85A was developed at Oxford University and was tested in nearly 2,800 infants in South Africa who had already been given a BCG shot, between 2009 and 2011. About half of the babies got the new vaccine while the other half got a placebo.

They were followed for up to three years. In the group that got the vaccine, there were 32 cases of TB, versus 39 cases in the group that got a placebo. The vaccine's efficacy rate was about 17 percent.

No serious side effects related to the vaccine were reported.

The study was paid for by Aeras, the Wellcome Trust and the Oxford-Emergent Tuberculosis Consortium. The results were published online Monday in the journal Lancet.

"There is much that we and others can learn from the study and the data it has produced," said Helen McShane of the University of Oxford, one of the study authors, in a statement. She and colleagues are further analyzing the samples from the trial to better understand how humans become infected with TB bacteria.

McShane and her co-authors wrote that the vaccine could potentially protect adolescents or adults against TB since their immune systems work differently from those of infants. The shot is also currently being tested in people with HIV.

"If this vaccine is effective in adults, that would be hugely valuable because the majority of TB disease and deaths are among adults," said Richard White, an infectious diseases expert at the London School of Hygiene and Tropical Medicine. "But no one knows the answer to that right now."

"A vaccine is likely to be a cost-effective way of preventing TB," he said, comparing the $650 million that has been invested into vaccine development in the past decade versus the more than $4 billion it currently costs to control the disease every year, according to the World Health Organization.

White also warned the world couldn't afford to ignore the spike in TB and its drug-resistant forms. "There are certain boroughs of London that have higher rates of TB than parts of Malawi," he said. "TB is such a big problem that we really need to throw the book at it."

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Drug showed promise in clearing drug-resistant tuberculosis

The Food and Drug Administration on Monday approved a Johnson & Johnson tuberculosis drug that is the first new medicine to fight the deadly infection in more than four decades.

The agency approved J&J's pill, Sirturo, for use with older drugs to fight a hard-to-treat strain of tuberculosis that has not responded to other medications. However, the agency cautioned that the drug carries risks of potentially deadly heart problems and should be prescribed carefully by doctors.

Roughly one-third of the world's population is estimated to be infected with the bacteria causing tuberculosis. The disease is rare in the U.S., but kills about 1.4 million people a year worldwide. Of those, about 150,000 succumb to the increasingly common drug-resistant forms of the disease. About 60 percent of all cases are concentrated in China, India, Russia and Eastern Europe.

Sirturo, known chemically as bedaquiline, is the first medicine specifically designed for treating multidrug-resistant tuberculosis. That's a form of the disease that cannot be treated with at least two of the four primary antibiotics used for tuberculosis.

The standard drugs used to fight the disease were developed in the 1950s and 1960s.

"The antibiotics used to treat it have been around for at least 40 years and so the bacterium has become more and more resistant to what we have," said Chrispin Kambili, global medical affairs leader for J&J's Janssen division.

The drug carries a boxed warning indicating that it can interfere with the heart's electrical activity, potentially leading to fatal heart rhythms.

"Sirturo provides much-needed treatment for patients who have don't have other therapeutic options available," said Edward Cox, director of the FDA's antibacterial drugs office. "However, because the drug also carries some significant risks, doctors should make sure they use it appropriately and only in patients who don't have other treatment options."

Nine patients taking Sirturo died in company testing compared with two patients taking a placebo. Five of the deaths in the Sirturo group seemed to be related to tuberculosis, but no explanation was apparent for the remaining four.

Despite the deaths, the FDA approved the drug under its accelerated approval program, which allows the agency to clear innovative drugs based on promising preliminary results.

Last week, the consumer advocacy group Public Citizen criticized that approach, noting the drug's outstanding safety issues.

"The fact that bedaquiline is part of a new class of drug means that an increased level of scrutiny should be required for its approval," the group states. "But the FDA had not yet answered concerns related to unexplained increases in toxicity and death in patients getting the drug."

The FDA said it approved the drug based on two mid-stage studies enrolling 440 patients taking Sirturo. Both studies were designed to measure how long it takes patients to be free of tuberculosis.

Results from the first trial showed most patients taking Sirturo plus older drugs were cured after 83 days, compared with 125 days for those taking a placebo plus older drugs. The second study showed most Sirturo patients were cured after 57 days.

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By Reuters

The number of people who caught tuberculosis last year inched downward according to an estimate by the World Health Organization, but the agency warned that drug-resistant strains are still spreading.

In a new report issued Wednesday, the U.N. agency estimated there were about 8.7 million new cases of TB last year, down from about 8.8 million in 2010. The number of deaths was unchanged at about 1.4 million — making it the second-leading killer among infectious diseases after AIDS.

But no one knows for sure what the actual figures are since the WHO report said it was too expensive and complicated to measure the exact number of new TB cases every year.

WHO also said drug-resistant tuberculosis was spreading but acknowledged it didn't have enough data to know if those strains were getting more prevalent or not.

Drug-resistant TB is often the result of patients not being treated properly for regular TB; it is more expensive to treat and the drugs have worse side effects. WHO estimates that only 1 in 5 cases of drug-resistant TB are identified globally, meaning the others are spreading the disease without being treated.

A look at various regions:

• EASTERN EUROPE AND CENTRAL ASIA: These regions have the world's highest rates of drug-resistant TB, including 62 percent of previously treated patients in Uzbekistan and 75 percent of such cases in Belarus. Much of the disease's spread here is driven by intravenous drug users and weak health systems that don't identify and treat patients early enough.
• INDIA AND CHINA: These two countries have almost 40 percent of the world's TB cases. India and China also have a rising number of drug-resistant cases even though both countries claim to treat about 90 percent of their TB patients. Last year, India reported several cases of totally resistant TB that were untreatable.
• AFRICA: About 25 percent of the world's TB cases are in Africa, where the death rate is the highest in the world. The HIV epidemic is also fueling the spread of TB in sub-Saharan Africa. Patients with HIV often have weaker immune systems, making them more susceptible to catching TB. At least one-third of HIV patients also have TB and about one-quarter of deaths in people with HIV are due to TB.
• AMERICAS, MIDDLE EAST AND WESTERN EUROPE: While the fewest number of TB cases are found here, the disease is on the rise in some cities including London, due largely to global travel patterns. The bacteria are spread easily in the air and people need only to inhale a few of the germs to be infected.

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