World TB Day 2012 questions and answers

March 20, 2012

Posted by Gitau Mburu

Senior Advisor, Health Systems and Services, International HIV/AIDS Alliance

This week, to mark World TB Day 2012 (24 March), I will be answering questions on TB and HIV.

First we look at HIV and TB service integration, and further down the page I have posted answers to questions readers sent in via the Alliance’s social networks.

What is the connection between HIV and TB?

TB is the most common opportunistic infection and cause of death among people living with HIV. In 2010, 1.1 million people with TB were also co-infected with HIV and 350,000 people living with HIV died from tuberculosis as reported in the WHO TB report 2011.

Why is it so important to integrate HIV and TB services?

There is growing evidence that integrating HIV and TB has significant benefits: It improves the survival of people living with HIV, is cost efficient, promotes cross-programme learning and has a major impact on patient outcomes, including increased access to services, reduced mortality among people living with HIV and higher cure rates among TB patients.

However, despite significant overlapping epidemiology globally, efforts to tackle TB and HIV have been largely separate. This makes it difficult to achieve universal and equitable access to HIV and TB prevention, treatment and care services. TB-HIV co-infection is a major cause of sickness and death. For this reason, TB and HIV should be addressed together.

What is the Alliance doing to integrate HIV and TB services around the world?

Integrating TB and HIV is a strategic objective of the Alliance. This started with an organisational TB strategy and a set of capacity building initiatives and implementation tools to increase the ability of our linking organisations to tackle TB.

The Alliance implements a range of activities to tackle TB:

•    Firstly, it supports a range of community based TB activities, including: involvement of people living with HIV in health service delivery; linking communities and health systems to strengthen referral systems and infection control; supporting delivery of community-based DOTS (Directly Observed TB Treatment, Short-course); secondment of community health workers to TB clinics to provide HIV counselling and testing and referrals; and implementing mobile sputum collection as a model for intensified case finding.

•    Secondly the Alliance supports strategic partnerships to tackle TB including collaboration with national TB programmes and initiating collaborative partnership with TB service providers and community-based organisations.

•    Thirdly, the Alliance supports advocacy at international national and local levels through dialogue with policy and decision makers, donor organizations, and working with journalists and key correspondents to advocate for TB services.

•    Fourthly, the Alliance implements anti-stigma programmes including the development of training material, anti-stigma tool-kits, training of trainers and  training on TB/HIV stigma for health care workers.

•    In addition, the Alliance provides care and support to people living with HIV and TB including clinical services to people co-infected with HIV and TB, referrals for TB screening and treatment, community-based DOTS, and capacity-building of local civil society organisations to provide care and support to people with HIV or TB.

•    We support knowledge sharing across the Alliance through communities of practice on TB/HIV and through dissemination of best practices and standards in HIV/TB integration through a variety of publications and case studies.

•    Finally the Alliance provides technical assistance in TB and HIV work within the Global Fund grants.

You can read more about TB and HIV here.

Your questions

Why aren’t confirmed TB cases mandatorily tested for HIV?

From Hari Singh, India, via Linked In

Global WHO policy on collaborative TB/HIV activities recommends that all confirmed and presumed TB cases should be offered routine HIV testing.  However, HIV tests should be offered on a voluntary, rather than mandatory basis. A person who is offered HIV testing may opt not to take the test. Informed consent should be obtained and confidentiality protected. It would be unethical to compel a person with TB to test for HIV infection against their wish and in direct violation of their rights. Consequently, raising awareness of the importance of testing for HIV among people with TB to increase their voluntary uptake of HIV is critical.

I am writing my dissertation on TB within England, a low-risk area, but do we underestimate the risk of TB in Europe?

From Alex Baskerville, UK, via Twitter

Estimation of incidence, prevalence and mortality of TB is based on modelling of information gathered through surveillance systems (such as case notifications and death registrations), expert opinions and consultations with countries, with underlying assumptions.

No country has ever undertaken a nationwide survey of TB incidence because this would be a major undertaking requiring large sample sizes and financing. Thus it’s possible that there are errors in the estimated incidence figures. In addition, the estimation of the risk of TB (i.e relative risk or odds ratio) depends not only on the country but the specific context. Underreporting of TB cases can particularly affect estimated rates. Overall, there is general consensus that the risk of TB is much higher in Eastern Europe compared to England, especially among prisoners and other marginalised populations.

Why isn’t TB literature available at DOTS-ICTC-PPTCT centres? Why aren’t HIV counsellors appointed at ICTC-DOTS? Why isn’t there a TB-HIV toll-free Helpline in India?

From Hari Singh, India, via Linked In

One of the most important barriers to the control of TB in many countries is the lack of knowledge of TB in communities. It is therefore important to promote information, education and communication on TB prevention, treatment and care as provided by national and international standards, such as the international standards for TB care. In addition, the World Health organization policy guidelines for national programmes and other stakeholders on collaborative TB/HIV activities recommend that HIV testing and counselling should be provided to patients with conformed or presumed TB disease.

What are the proper guidelines on TB screening? Which symptoms are key when asking screening questions?

From Wynnette Chinogwenya, South Africa, via Linked In

The objective of screening for TB is to promptly identify people who are either at high risk of TB disease or who already have the disease in order to facilitate early treatment and prevention of transmission. Often, screening is based on symptoms (i.e complaints that patients have) and signs (i.e what a clinician finds upon physical examination on a patient).

-    Examples of TB symptoms: Cough, weight loss, night sweats, fever. Etc
-    Examples of TB signs: Stiff neck, confusion, poor air entry in the lungs, lymph node swelling etc

In general terms if you want to identify all people who might have TB then you would use all of the above signs and symptoms in any combination.

If you use screening that is based on the presence of at least one sign or symptom, you would be over-estimating TB disease because there are many causes of each one of these symptoms. For instance, TB is not the only cause of cough or fever.

On the other hand if you use screening which is based on the presence of all the above signs and symptoms, then you would miss a lot of people who have TB because majority of people with TB present with only a few of these signs and symptoms.

Thus, screening guidelines are a trade off between what combination of signs and symptoms are most predictive of TB in a specified population. This trade off is based on the concept of sensitivity and specificity. Most commonly, this is taken to be a combination of chronic cough of more than 2 weeks, weight loss, night sweats, and fever (all of which cant be explained by any other obvious reason). However, and as noted above, this is not a perfect screening protocol.  In addition, screening protocols can be adjusted based on the nature of the TB epidemic and the population. Other factors such as exposure to someone who has pulmonary TB are often considered.

In conclusion, there is no perfect TB screening protocol, but most use a combination of signs and symptoms that are most predictive of TB disease in a specific setting.

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