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TB and HIV: A deadly combination

Though TB is a preventable and curable disease, more than 40% of adults in India are infected and 364,000 people die of it every year. Hemlata Jiwnani explains how this frightening scenario is complicated by drug resistant strains and HIV

“We cannot fight AIDS unless we do much more to fight TB” ---Nelson Mandela, at the XIV World AIDS Conference, Bangkok 2004

The global public health problem of tuberculosis and HIV is beginning to concern policy makers, activists and other leaders. It dominated the XVII International AIDS Conference in Mexico in August 2008. Though earlier conferences have had tuberculosis (TB) as one of the subjects of discussion, this was the first time that tuberculosis dominated an HIV conference, with satellite discussions and also a protest held by health activists and HIV-positive people to mainstream TB treatment in HIV programmes.

A few months earlier, in June 2008, the UN held the HIV/TB Global Leaders Forum in New York, for the first time bringing together world leaders and decision makers to accelerate the fight against this dual epidemic.

TB as a public health concern

Tuberculosis remains a worldwide public health problem despite the fact that the causative organism Mycobacterium tuberculosis was identified a hundred years ago by a German physician, Robert Koch. The infection commonly affects the lungs (pulmonary TB), though it can infect any part of the body (except the hair and nails). TB bacilli are transmitted from person to person through the air, in the same way that the common cold is. Not all people who breathe in the bacilli get infected and not all those who are infected get TB disease. A person with TB infection has a 10% risk of developing TB disease during his/her lifetime. Those with low immunity are more prone to develop the disease.

In earlier days the disease was called “consumption” as there was no effective treatment and people with the disease would literally waste away. For some decades now, effective antibiotics are available, making TB a curable disease. Further, the BCG vaccination (Bacillus Calmette-Guerin, named after Calmette and Guerin who developed the vaccine) is believed to be effective in preventing the meningeal form of TB that infects the brain and central nervous system. In India, under the Universal Immunisation Programme, the BCG vaccine is administered before the child is one month old.

Prevalence, incidence and deaths

Approximately 2 billion people worldwide are infected with TB. There were approximately 9.2 million new cases of all forms of TB (pulmonary and extra-pulmonary) worldwide in 2006, of which the vast majority occurred in developing countries. (1)

Though TB is a preventable and curable disease, it killed an estimated 1.5 million people in 2006.(2) It is one of the top 10 causes of death at all ages worldwide. (HIV/AIDS killed an estimated 2 million people worldwide in 2004.) The vast majority of deaths from TB were in developing countries with more than half of all deaths occurring in Asia.

Drug resistant TB

Of the 9.2 million new cases of TB every year, 489,000 are of multi drug resistant TB (MDR-TB) and another 30,000-40,000 are of ‘extremely drug resistant’ or XDR-TB. (3) MDR-TB develops when treatment is not completed, leading to the development of bacteria resistant to at least two of the best anti-tuberculosis drugs, isoniazid and rifampicin, which are considered to be the first line of treatment. The drug resistant strain of TB is then transmitted to others.

Drug resistant TB can be difficult to treat and very expensive in developing countries due to lack of availability of second line treatment in the public health sector as part of the national tuberculosis control programme (pilot studies in Gujarat and Nagpur, Maharashtra are on-going). XDR-TB is MDR-TB plus resistance to a second line injectable drug and a fluroquinolone. Both types of TB can be primary or acquired, depending on the patient’s history of past TB treatment.

HIV/TB co-infection

We know that HIV infection compromises the immunity of infected people, making them susceptible to a number of infections. TB is one of the earliest opportunistic infections and the most common such infection that occurs in patients with HIV. For an HIV-positive person, TB disease is an AIDS defining illness.

In fact, one third of the 33.2 million people living with HIV world wide are also infected with TB. HIV-positive people have a 60% lifetime risk of developing TB, compared to a 10% lifetime risk in HIV-negative people. The risk of recurring TB is higher in people living with HIV, thus increasing their risk to MDR-TB as well as XDR-TB. It is estimated that of the 1.5 million people who died of TB in 2006, about 200,000 were infected with HIV. (4)

An increase in TB cases among people living with HIV may lead to an increase in risk of TB transmission to the general population. Increasing rates of TB in the recent decade are directly related to HIV/AIDS.

The Indian scenario

In India more than 40% of adults are infected with tuberculosis and 0.3% have active TB disease at any given time. There are 1.9 million new cases of TB in India every year, of which 870,000 are infectious.(5) 364,000 adults and children die of TB every year in India. In comparison, 361,000 people die annually because of HIV.(6) This translates into about 1,000 deaths a day from TB, or two every three minutes. India contributes one-fifth of the global burden of tuberculosis. According to the National Aids Control Organisation (NACO), an estimated 0.36% or 2.5 million of all people aged 15-49 are living with HIV/AIDS.

Currently, more than 1.7 to 2.2% (according to studies conducted by the Tuberculosis Research Centre, Chennai, and the National Tuberculosis Institute, Bangalore) of new TB cases in India are identified as MDR-TB. As many as 12% of people who return for treatment because the disease has relapsed are found to have MDR-TB, and developed the resistant strain as a result of incomplete treatment. Treatment for MDR-TB may take up to two years, with more adverse side effects and is 3,000 times more expensive than first-line treatment.

Social context

Tuberculosis is a disease complicated by complex socio-economic problems such as unemployment, poverty, malnutrition and poor living conditions. TB is more prevalent in poorer communities or areas that are overcrowded and poorly ventilated. People living in such conditions are exposed to high doses of bacilli. Also patients who are malnourished have lower resistance to TB bacilli.

Once a patient develops the disease, problems increase manifold in terms of inability to work, difficulty in gaining access to treatment, and delay in treatment due to ignorance. TB results in the loss of 20 to 30% of the annual household income. When an individual dies from the disease, an average of 15 years of income is lost for the household. Children leave school to work because their parents have TB. Adding to this problem are the increasing cases of MDR-TB and XDR-TB which require more expensive drugs and are therefore a much greater burden on the poor.

Social stigma is of major concern to women with TB in India and this affects their status as wife or mother. Women with TB are often rejected by their families. This stigma adds to the illness burden and may prevent people from using diagnostic and treatment services, or delay such efforts. It may also result in termination of treatment.

For diseases like TB and HIV that are highly stigmatised, the social impact of the disease may be at least as great a source of suffering as the physical symptoms of the disease. As the diseases are interrelated, this has given rise to a new TB-HIV stigma that impairs the quality of life more than in the case of the individual disease. Though stigma and discrimination related to TB may be less severe, and the disease is more accepted by the community and therefore by the patient, co-infection with HIV worsens the scenario and may lead to outright social rejection of patients. Both the diseases are chronic and require long-term care and support and adherence to treatment. The dual stigma will lead to difficulty in getting access to care and support.

Another difficulty faced by patients is related to healthcare. In a country like India, more than 86% of TB patients as reported by Uplekar and Rangan (7) in 1998 use the private healthcare system, where treatment is not standardised. Even the statistics on both diseases do not include information from the private sector. And at the same time, people find it difficult to approach the public health system which is already weak. TB control is still a dream in a country like India, though it has one of the largest TB control programmes in the world.

Preventing TB in HIV infected patients should be the main thrust of any programme that tries to control the two global epidemics, especially as TB is easily transmitted through the air. Much needs to be done to contain mortality from both the diseases. Though international and national policies to tackle the dual epidemic are getting priority, and coverage is improving, not much has been achieved in implementation of activities.

The first step towards giving a better life for patients is to recognise that the threat caused by TB/HIV co-infection requires urgent intervention. Apart from technical frameworks and policy guidelines, research on newer drugs and vaccines and political commitment will play an important role in this effort.

Note: HIV prevalence figures for India have been revised in 2006-07; hence websites using earlier estimation show a much higher figure (5.1 million as compared to revised ones that are between 2.0 to 3.1 million).

(Hemlata Jiwnani is a project co-ordinator with a non-governmental organisation in Mumbai. She works on involving the private sector in improving the slum population's access to services available under the Revised National TB Control Programme)

Endnotes

  1. http://www.who.int/tb/publications/2008/factsheet_april08.pdf
  2. http://www.who.int/tb/en/
  3. http://www.stoptb.org/wg/tb_hiv/assets/documents/Fact%20sheet%
    20HIV%20TB%20for%20IAS%20FINAL.pdf
  4. http://www.who.int/tb/en/
  5. http://www.whoindia.org/en/Section3/Section123.htm
  6. http://www.who.int/whosis/mort/profiles/mort_searo_ind_india.pdf
  7. Uplekar M, Rangan S, ‘Tuberculosis patients and practitioners in private clinics in India’, International Journal of Tuberculosis and Lung Disease, April 1998, volume 2 (issue 4): pp. 324-9.

InfoChange News & Features, November 2008