Tuberculosis

March 24 Is World TB Day

March 24 is World TB Day, an opportunity to raise awareness about tuberculosis (TB) and the need for expanded testing and treatment worldwide. The latest data from the CDC indicate that TB cases in the U.S. have reached an all-time low of 9412 cases, but the decline has slowed. Globally, the World Health Organization (WHO) estimates that 9 million people fell ill with TB -- including 480,000 with multidrug-resistant TB -- and 1.5 million people died from the disease in 2013. An estimated 1.1 million people living with HIV were coinfected with TB in 2013, and TB is among the leading causes of death for HIV-positive people, accounting for 25% of all HIV-related deaths.

TB Worldwide

Some 2 billion people worldwide are thought to be infected with Mycobacterium tuberculosis (the bacteria that cause TB), of whom 1 in 10 will go on to develop active disease. An estimated 3 million people with TB are never diagnosed, given preventive therapy, or treated, and therefore are at risk for developing severe disease -- most often affecting the lungs -- and can continue to transmit TB to others.

"Among those missed are those most vulnerable to falling ill with TB including very poor and/or malnourished or undernourished people, people living with HIV/AIDS, children and women, migrants, prisoners, refugees and internally displaced persons, miners, the elderly, ethnic minorities, indigenous populations, drug users, and homeless persons," the organization stated.

WHO says that the estimated number of people falling ill with TB each year is declining, albeit very slowly, and the world appears to be on track to meet the Millennium Development Goal of reversing the spread of TB by 2015.

TB in the U.S.

In advance of World TB Day, the Centers for Disease Control and Prevention (CDC) released its latest TB surveillance report for the U.S., showing that TB control programs are working, but progress appears to be slowing.

The report, published in the March 20 Morbidity and Mortality Weekly Report, includes data submitted to the CDC's National Tuberculosis Surveillance System for 2014. According to the report, the total number of cases in 2014 was the lowest ever reported -- at 9412, or 3.0 per 100,000 persons -- but the 2.2% decrease since 2013 was the smallest decline in 2 decades.

The report indicates that there continue to be major disparities in who has TB in the U.S. The rate for foreign-born individuals is 13 times higher than that of people born in the U.S., accounting for 66.5% of all cases. More than half originated from 5 countries: China, India, Mexico, the Philippines, and Vietnam.

Asians have the highest rate of all racial/ethnic groups -- accounting for 2,961, or nearly one-third of all cases -- which is 29 times higher than that of whites and 8 times higher than that of African-Americans or Hispanics/Latinos. However, this represents a decrease from the 2013 rate. 96% of Asians, 76% of Hispanics, 42% of blacks, and 23% of whites with TB were foreign born.

In 2014, 6.3% of people with TB who had a known test result were coinfected with HIV, and 5.5% of adults with TB reported being homeless within the past year.

Multidrug-resistant TB (MDR-TB) accounted for 1.3% of all TB cases and there was 1 case of extensively-drug resistant TB (XDR-TB) reported for 2014. MDR-TB is resistant to at least 2 first-line therapies, while XDR-TB is resistant to almost all available drugs. Treatment for resistant TB is more difficult to tolerate, lengthier, and costlier, and the disease is more likely to be fatal.

"Despite the continued decline in U.S. TB cases and rates since 1993, the 2.2% decrease from 2013 to 2014 to a rate of 3.0 per 100,000 still does not achieve the goal of TB elimination," the report authors concluded. "This decline in the rate of TB was the smallest decrease in more than a decade and suggests the need for ongoing evaluation of TB elimination strategies overall and within high-risk populations."

Call to Action

Earlier this month nearly 90 advocacy organizations -- including Médecins Sans Frontières/Doctors Without Borders, the South African Treatment Action Campaign, and the U.S. Treatment Action Group-- sent a letter requesting national and international funders and pharmaceutical companies to increase access to new treatments including bedaquiline (Sirturo) and delamanid (Deltyba) -- the first TB drugs to be approved in more than 40 years.

"New drugs to treat [drug-resistant] TB have finally been developed; yet long after their approval, they are only available to a small number of those who need them," the letter states. "We call upon you to work together with in-country partners to urgently make these drugs available to patients to both save their lives and stop ongoing transmission of highly resistant strains in the community."

The WHO also issued a call for action, noting that there is an annual gap of about US$2 billion between current funding and what is needed to ensure a full response to the global TB epidemic, as well as an additional $1.39 billion for research including development of new diagnostics, treatments, and vaccines.

"The progress that has been made in combating TB has been hard won and must be intensified if we are to wipe out the TB epidemic," said Eric Goosby, UN Special Envoy on TB. "It is time to join forces to create a world free of TB."

Resources

• CDC: World TB Day
• CDC: TB in the United States: A Snapshot, 2014
• CDC: TB Drug Resistance in the U.S.
• CDC: Tuberculosis Overview
• Stop TB Partnership: World TB Day
• World Health Organization: World TB Day 2015

3/24/15

Sources

CDC. TB in the United States: A Snapshot, 2014. Fact sheet. March 2015.

C Scott, HL Kirking, C Jeffries, et al. Tuberculosis Trends -- United States, 2014. Morbidity and Mortality Weekly Report 64(10):265-269. March 20, 2015.

Médecins Sans Frontières, et al. Call to action: Accelerate access to DR-TB drugs. March 10, 2015.

Stop TB Partnership/UNOPS. World TB Day 2015: "Reach the 3 Million: Reach, Treat, Cure Everyone."

World Health Organization. WHO calls on the world to "Gear up to End TB." News release. March 19, 2015.