Fast Facts: TB and HIV

(Photo credit: WHO/TBP/Davenport)

Tuberculosis (TB) is a contagious disease caused by mycobacterium tuberculosis in any part of the body. It is transmitted through aerosolized droplets after infected people cough, sneeze or speak.

HIV stands for ‘human immunodeficiency virus’, the virus that causes AIDS

**More than 5,000 people die every day from TB despite a cure having been available for 50 years.

**TB is a leading killer of people infected with HIV.

**TB accounts for about 13% of AIDS deaths worldwide.

**In Africa, HIV is the single most important factor determining the increased incidence of TB in the past 10 years.

**People living with HIV are up to 50 times more likely to develop TB than those who are not infected.

**If TB is left unchecked, almost one billion people will become newly infected in next 20 years, over 150 million will become ill and 36 million will die of TB.

**TB is the biggest curable infectious killer of young people and adults.

**In most of East and Southern Africa, less than one patient in three receives a full course of TB drugs.

**TB causes more deaths among women than all causes of maternal mortality combined.

**TB is curable, even in people living with HIV. DOTS (daily observed treatment, short-course) is the internationally recommended strategy for TB control.

These facts were compiled from various web sources including, World Health Organization (WHO), Stop TB Partnership and the Centers for Disease Control and Prevention (CDC), http://www.who.int/mediacentre/factsheets/fs104/en/, http://www.cdc.gov/hiv/pubs/facts/hivtb.htm.

Preventive TB therapy – the obvious HIV link

"VCT CENTRES ARE ONE OF THE FEW PLACES AT WHICH LARGE NUMBERS OF HIV-INFECTED PPD-POSITIVE PEOPLE MAY BE IDENTIFIED EFFICIENTLY"

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Prior to the HIV epidemic, preventive TB therapy was less cost-effective than finding and treating active TB particularly in low-income countries with a high prevalence of TB.

Today in many such settings, however, a significant number of HIV-infected adults (estimated between 2.4 and 7.5%) will develop active TB each year. Among those with a positive TB skin test (purified protein derivative, or PPD), the rates of active TB are even higher (3.4 to 10% per year; Markowitz N et al 1997).

This prompted WHO and UNAIDS, in 1998, to recommended preventive TB therapy for PPD-positive, HIV infected people who do not have active TB.

Despite this policy recommendation, TB preventive therapy programs remain to be implemented in almost all countries with high HIV prevalence. Dr Paul Nunn, Coordinator of TB/HIV and Drug Resistance at WHO in Geneva, attributed this lack of action to the failure by country health managers to grasp the critical connection between HIV and TB disease. He hastened to add though that in countries where DOTS coverage or effectiveness at finding and curing TB is not good, DOTS implementation remains the key priority.

DOTS is yet to succeed in countries were primary health care programs (PHC) are not functional. Such countries tend to be very low-income countries, many of which also have very high prevalence of HIV infection. Poor PHC systems present insurmountable difficulties for health care interventions such as DOTS, as highlighted in the recent WHO Report on Global TB Control.

Inevitably, HIV has worsened the TB picture. But the message that those infected with mycobacterium tuberculosis - without active disease - may be identified and given preventive therapy before their TB becomes active, has not received sufficient attention. Ultimately offering a holistic care package - to include but not be limited to TB preventive therapy can probably only be achieved through the rapid integration of HIV and TB programs at all levels.

Dr Adatu, National TB Program Manager in Uganda, conceded that at the moment in Uganda TB preventive therapy cannot be incorporated in the program. He has however, encouraged and permitted AIDS service organizations that are well organized and have the capacity to implement preventive therapy to do so. A case in point is the AIDS Information Center, the largest and oldest voluntary counselling and testing (VCT) centre in the country. Since 2000, the centre has added TB preventive therapy and TB treatment services to existing VCT activities - in collaboration with the US Centers for Disease Control and Prevention Global AIDS Program in Uganda.

Implementing TB preventive therapy programs is challenging. It requires the identification of HIV-infected people early enough before their immune systems are run down. VCT centres are one of the few places at which large numbers of HIV-infected PPD-positive people may be identified efficiently. But most VCTs are not even thinking about TB, and are not equipped to eliminate possibly active TB infection. At best, this means that the only outcome under these circumstances is referral to another health centre or hospital that deals specifically with TB.

Before initiating preventive TB therapy, active TB must be excluded and only those with a positive tuberculin skin test (PPD) are most likely to benefit. HIV infected people with advanced disease are often non-reactive to PPD tests and would not benefit from preventive therapy anyway. Furthermore, it is difficult to diagnose TB in HIV-infected individuals, since most are sputum smear negative (and hence non-infectious for TB), even though a significant number may have extrapulmonary TB. As with all drug-based prevention strategies, ensuring adequate adherence to preventive TB therapy is another potential challenge.

One way to manage dual HIV/TB infection - and deliver TB preventive therapy as well as DOTS for those presenting with active TB - would be to establish comprehensive HIV care clinics. In which VCT, DOTS, antiretroviral drugs (ARVs), prevention of mother-to-child HIV transmission services (PMTCT), prevention and treatment of other OIs is offered as a total package.

Better links between HIV care and TB control services would almost certainly increase access to TB preventive therapy for people living with HIV and would enhance performance of the TB strategy.

The 'observed' part of the DOTS strategy could also be usefully employed to ensure adherence to preventive therapy, since defaulting from therapy is a legitimate concern.

HDN Key Correspondent
Email: correspondents@hdnet.org

[Note: This report was based on discussions and interviews held during the 2nd Stop-TB Partners Forum in New Delhi]

Is treatment of tuberculosis in Malawi prolonging the lives of people with HIV/AIDS?

Over the last 15 years, tuberculosis (TB) case numbers have increased 300-400% in Malawi, in conjunction with a rise in HIV infection. This is primarily because HIV increases the risk of disease reactivation in people with latent tuberculosis infection, and also because it increases susceptibility to new TB infections.

There are currently over 24,000 cases of TB registered across Malawi, 77% of whom are estimated to be HIV/AIDS positive. Although Malawi is regarded internationally as a star performer in effective TB treatment using “direct observed therapy, short-course”, or DOTS – which boasts 100% nationwide coverage – a large percentage of HIV positive people continue to die of TB-related illnesses.

Numerous studies carried out in the last 15 years show that preventive treatment of TB in people who are HIV positive helps them live longer. If these studies are to be believed, then one would expect HIV/AIDS mortality in a country with 100% TB treatment coverage to have been reduced greatly.

Unfortunately, the situation is exactly the opposite, and a lot of HIV positive people continue to die of TB infection. Can there be another factor that is contributing to TB treatment failure in HIV positive patients?

The answer is definitely yes. A low socioeconomic status among the population, coupled with a poor healthcare system in general, is the likely explanation for high HIV mortality rates due to TB.

Malawi is currently among the ten poorest countries in the world. It has a population of 11 million people, of which 65% live on less than one US dollar per day. Agriculture forms the economic backbone of the country, and almost all indigenous Malawian farmers are involved in subsistence farming using manual labour.

However, the trend over the past ten years has been for households practicing subsistence farming to produce only sufficient food for two to three months after harvesting. After that, families usually depend on piecework, handouts and wild foodstuffs for survival. This situation makes the maintenance of good health among Malawians difficult.

Generally, it is the adult members of the family who are involved in cultivation. Unfortunately, those most vulnerable to TB and HIV/AIDS infection are the labour providers and more senior members of the family.

This division of labour impacts negatively on the ability of people infected with HIV or TB to access treatment. Put simply, most patients would rather spend time looking for ways to support their families than be in a hospital bed. In most cases, therefore, patients are only referred to hospital after they become severely ill and are too weak to work.

A study by Bertha Simwaka, a senior researcher at the Equi-TB Knowledge Programme in Malawi found that over 67% of deaths among HIV/TB-infected patients are due to treatment failure caused by lack of proper nutrition to support the immune system.

Another study on the impact of AIDS on rural livelihoods in southern Malawi found that 62% of sampled rural households only ate meals five or less days per week. In most cases they only had one meal per day.

However, the development of tuberculosis following exposure to TB micro-organisms is usually prevented by the immune system. When immune system effectiveness is reduced by HIV, the TB micro-organisms, which are dormant within the body of an individual who has been infected, begin to multiply, causing the disease.

When a person is found to have TB, they should be admitted to hospital or healthcentre for at least two to eight weeks. During this time patients receive curative drugs, which are usually very strong and tend to weaken the body. This has resulted in patients dying faster because their bodies cannot sustain the energy requirements of the treatment. For example, clinical studies from Lilongwe central hospital showed that 31% of patients dropped out of treatment due lack of food. Hence the need for energy-giving food as an integral part of treatment.

A clinical officer at Mchinji district hospital in central Malawi explained that a number of patients there have either refused or defaulted treatment because they cannot afford to spend eight weeks in hospital away from their farms. Farming activities clearly override the need for treatment. But poor adherence leads to unnecessary infection and death.

The situation is worse for people with HIV as their immune systems are already greatly weakened.

Another complication is the general belief among Malawians that all people with TB also have HIV. This has led in many cases to delayed TB diagnosis, because those with TB are afraid they will be labelled as HIV-infected, which would deny them the chance to share in communal money making activities. In most cases delayed diagnosis leads to poorer treatment outcomes.

Although TB treatment coverage in Malawi is 100%, deficiencies in the health system itself also impede the effective treatment of all TB cases. The health sector in Malawi is greatly understaffed, with 70% of the established posts in the ministry of health unfilled. This is undermining the effective administration of diagnosis and treatment. As a result, some people wanting treatment have been denied it.

The country also has very few microscopy centres, and health facilities in areas far from the ones that exist are supposed to use their own means to get to them. In order to reduce travel costs, health workers store up sputum samples over a period of time. The danger is that there may be a mix-up of samples, or samples may get damaged in storage. Such errors cause further delays in getting test results. There is therefore a real chance for patients to develop full-blown TB while they are waiting for their test results.

In conclusion, Malawi shows how a lack of sound developmental interventions to improve the livelihoods of poor people are greatly undermining initiatives to prolong the lives of those affected by HIV/AIDS and TB. There is an urgent need for local and international leaders to reconsider their development priorities, and begin improving the economic status of poor people and the health systems they depend upon. Only in this way can universal access to quality health care be assured.

HDN Key Correspondent
Email: Correspondents@hdnet.org

(July 2004)

Tuberculosis control: How can we do better?

In July 2004, Nelson Mandela called on the world to:

...recognise that we can’t fight AIDS unless we do much more to fight TB as well.

Is there scope to improve tuberculosis control to extend the lives of people living with HIV? Some of the areas for improvement are considered below.

Interventions to reduce death rates in patients with tuberculosis in countries with high HIV prevalence:

• Reducing the delay between symptoms starting and diagnosis.
• Improving the diagnosis of smear-negative pulmonary tuberculosis and extra-pulmonary tuberculosis.
• Improving the treatment of smear negative tuberculosis.
• Research on the role of adjunctive treatments such as corticosteroids and antibiotic prophylaxis.
  Monitoring the quality of clinical care.
• Protecting healthcare workers from occupationally acquired tuberculosis.
• Protecting patients with AIDS from nosocomial tuberculosis (disease acquired in a health care facility).

Reducing the delay

A delay of three to four months between symptoms starting and diagnosis is typical in Africa. These delays result in more advanced TB and a decline in the immune status of someone with AIDS. The causes for these delays are many and will include patient perceptions of the disease, stigma, difficulty in accessing health facilities and the poor quality of these health services. Research may be required to determine the major reasons for delay in particular settings, but all of these causes can be addressed.

A further cause for the delay is the poor quality of laboratory services. Research in Pakistan showed that a large number of smear-negative samples turned out to be positive when retested in a good-quality laboratory.

The role of adjunctive and preventive treatments

Experience from Malawi suggests that 40% of deaths from tuberculosis occur in the first month of treatment. It is possible that the use of empirical antibiotics (to control other bacterial infections) and corticosteroids (to control reactions to the TB medicines) may reduce this death toll. The use of cotrimoxazole has been recommended by UNAIDS on the basis of results of studies in Côte d’Ivoire. However, it is unclear how widely this recommendation has been implemented.

Isoniazid is recommended for the prevention of tuberculosis in people with HIV infection who are exposed to the disease. It is uncertain how widely this intervention is used but almost certainly there will be considerable room for improvement.

Monitoring the quality of clinical care

The quality of clinical care is crucial to successful TB control. While outcomes are regularly monitored (e.g. cure and default rates) there might be scope for a better assessment of process measures (e.g. attendance for treatment or response to adverse events).

Experience with directly observed therapy for tuberculosis (DOTS) in Africa has been highly variable. Treatment completion rates vary from 37% (low) in the Central African Republic to 78% (moderate) in Kenya and Tanzania. These rates are inadequate to effectively control the disease.

Cost implications

Tuberculosis control is a highly cost-effective way of extending the lives of people living with HIV. Using prices from the year 2000, TB treatment in Africa costs US$10 for a full six-month course of drugs – or in economist’s terms, less than US$75 per Disability Adjusted Life Year (DALY) gained. This is similar to the cost-effectiveness of Nevirapine or Zidovudine for the prevention of mother-to-child transmission of HIV, or of voluntary counselling and testing. It is much more cost-effective than other interventions such as home care programmes and antiretroviral therapy which both cost several hundred dollars per DALY gained.

Conclusions

It is extraordinary that TB control remains far from excellent in so many countries with a high prevalence of HIV. Worse still, it is astonishing that so many basic questions about TB treatment in the context of HIV are still unanswered, for example the role of adjuvant treatments. Despite the recent and welcome additional investment in TB programmes that has come from the Global Fund to fight AIDS, TB and Malaria, there remains scope to do much more. Without good TB control, many of those alive with HIV today may not be around by the time antiretroviral programmes become available.

HDN Key Correspondent
Email: correspondents@hdnet.org

(July 2004)