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"
**
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]
**
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]
posted by AIDS-Care-Watch at 10:18 am
0 Comments:
Post a Comment
<< Home