Epidemiology

The World Health Organization (WHO) Global Tuberculosis  Report 2012 provides the latest information and analysis about the tuberculosis (TB) epidemic and progress in TB care and control at global, regional and country levels. It is based primarily on data reported by WHO’s Member States in annual rounds of global TB data collection. In 2012, 182 Member States and a total of 204 countries and
territories that collectively have more than 99% of the world’s TB cases reported data.

● Progress towards global targets for reductions in TB cases and deaths continues. The Millennium Development Goal (MDG) target to halt and reverse the TB epidemic by 2015 has already been achieved. New cases of TB have been falling for several years and fell at a rate of 2.2% between 2010 and 2011. The TB mortality rate has decreased 41% since 1990 and the world is on track to achieve the global target of a 50% reduction by 2015. Mortality and incidence rates are also falling in all of WHO’s six regions and in most of the 22 high-burden countries that account for over 80% of the world’s TB cases. At country level, Cambodia demonstrates what can be achieved in a low income and high-burden country: new data show a
45% decrease in TB prevalence since 2002.

● However, the global burden of TB remains enormous.In 2011, there were an estimated 8.7 million
new cases of TB (13% co-infected with HIV) and 1.4 million people died from TB, including almost one
million deaths among HIV-negative individuals and 430 000 among people who were HIV-positive. TB is one of the top killers of women, with 300 000 deaths among HIV-negative women and 200 000 deaths among HIV-positive women in 2011. Global progress also conceals regional variations: the African and
European regions are not on track to halve 1990 levels of mortality by 2015.

Burden of disease

Geographically, the burden of TB is highest in Asia and Africa. India and China together account for almost 40% of the world’s TB cases. About 60% of cases are in the South-East Asia and Western Pacific regions. The African Region has 24% of the world’s cases, and the highest rates of cases and deaths per capital.Worldwide, 3.7% of new cases and 20% of previously treated cases were estimated to have MDR-TB. India, China, the Russian Federation and South Africa have almost 60% of the world’s cases of MDR-TB. The highest proportions of TB patients with MDR-TB are in eastern Europe and central Asia.
Almost 80% of TB cases among people living with HIV reside in Africa. Estimating the burden of TB in children (aged less than 15) is difficult; estimates are included in the report for the first time. There were an estimated 0.5 million cases and 64 000 deaths among children in 2011.

Case notifications and treatment success

In 2011, 5.8 million newly diagnosed cases were notified to national TB control programmes (NTPs) and reported to WHO, up from 3.4 million in 1995 but still only two thirds of the estimated total of 8.7 million people who fell ill with TB in 2011.Notifications of TB cases have stagnated in recent years.
New policy measures, including mandatory case notification by all care providers via an electronic web-based system in India, could have a global impact on the number of TB cases notified in future years. Intensified efforts by NTPs to engage the full range of care providers using public-private mix (PPM) initiatives are also important; in most of the 21 countries that provided data, 10–40% of notifications were from non-NTP care providers. Globally, treatment success rates have been maintained at high levels for several years. In 2010 (the latest year for which treatment outcome data are available), the
treatment success rate among all newly-diagnosed cases was 85% and 87% among patients with smear-positive pulmonary TB (the most infectious cases).

Responding to drug-resistant TB 

Measurement of drug resistance has improved considerably. Data are available for 135 countries worldwide (70% of WHO’s 194 Member States) and by the end of 2012 will be available from all 36 countries with a high burden of TB or MDR-TB. Extensively drug-resistant TB, or XDR-TB, has been reported by 84 countries; the average proportion of MDRTB cases with XDR-TB is 9.0%. The target treatment success rate of 75% or higher for patients with MDR-TB was reached by only 30 of 107 countries that reported treatment outcomes.Scaling up TB-HIV collaboration Globally, 40% of TB patients had a documented HIV test result and 79% of those living with HIV were provided with co-trimoxazole preventive therapy in 2011.
Interventions to detect TB promptly and to prevent TB among people living with HIV, that are usually the
responsibility of HIV programmes and general primary health-care services, include regular screening for TB
and isoniazid preventive therapy (IPT) for those without active TB. The number of people in HIV care who were screened for TB increased 39% (2.3 million to 3.2 million) between 2010 and 2011. Nearly half a million people without active TB were provided with IPT, more than double the number started in 2010 and mostly the result of progress in South Africa.

Research and development to accelerate progress

Research to develop a point-of-care diagnostic test for TB and MDR-TB continues, and other diagnostic tests are in the pipeline.Today, standard treatment for TB patients lasts six months and the regimen for most patients with drugresistant TB takes 20 months. Treatment for MDR-TB is costly and can have serious side-effects. Of the 11 anti-TB drugs in clinical trials, two new drugs are being evaluated to boost the effectiveness of MDR-TB regimens. A novel regimen that could be used to treat both drug-sensitive
TB and MDR-TB and shorten treatment duration has shown encouraging results in clinical trials.
There is no effective vaccine to prevent TB in adults. Progress in the past decade means that it is possible that at least one new vaccine could be licensed by 2020.

Financing for TB care and control

About US$ 1 billion per year of international donor funding is needed for TB care and control (excluding TB/HIV interventions) in low and middle-income countries from 2013 to 2015, double existing levels. Up to an additional US$ 1 billion per year is needed for TB/HIV interventions, mostly for ART for HIV-positive TB patients.National contributions provide the bulk of financing for TB care and control in Brazil, the Russian Federation, India, China and South Africa (BRICS). However, they remain insufficient for scaling up the diagnosis and treatment of MDR-TB; BRICS account for about 60% of the world’s estimated cases of MDR-TB. The Global Fund provides almost 90% of international donor funding for TB.


reference: http://www.who.int/tb/publications/global_report/gtbr12_main.pdf