ITP can only be implemented if intensive case-finding for HIV-infected TB patients is already in place (Chapter 6).
16.4.1 HIV-infected adults and adolescents
IPT is safe and effective in HIV-infected patients; it reduces the risk of active TB by 33-64%1. It should be implemented in all settings having a high prevalence of TB and HIV.
Current evidence suggests that only HIV-infected adults having a positive TST benefit from IPT5. HIV-infected adults and adolescents without any of the four TB symptoms (cough, fever, weight loss, night sweats), and having a positive TST, should be offered long-term IPT (at least 36 months).
TST is not a prerequisite for IPT. In settings where TST is not feasible, HIV-infected adults and adolescents without any TB symptoms should be offered 6 months of IPT, which should be repeated every 3 years.
In eligible adults and adolescents, IPT should be initiated after 3 months of anti retroviral therapy (ART). Patients should have attended at least 2 clinic appointments, and they should have a good understanding of why IPT is being prescribed.
IPT has been shown to offer additional protection against TB in those on ART. However, initiation of ART should take priority over initiation of IPT.
In the subgroup of patients eligible and/or in the process of being started on ART, there is a high prevalence of undiagnosed TB, including a considerable proportion with no TB symptoms6. In this subgroup, it is reasonable to wait 3 months1 before considering initiation of IPT. During this time, TB symptom screening should be repeated at each clinic visit.
16.4.2 HIV-exposed and HIV-infected children
IPT should be given to children in 3 situations as long as symptom-based TB screening is negative (no current cough, no fever and no poor weight gain) or evaluation has not found active TB:
– Routinely: all HIV-exposed and HIV-infected children between the ages of 12 months and 15 years, regardless of contact history, should be given 6 months of IPT every 3 years;
– After contact3 with any case of TB (smear positive, smear negative and extrapulmonary): all HIV-exposed and HIV-infected children < 15 years of age should be given 6 months of IPT;
– Post-TB treatment: all HIV-exposed and HIV-infected children < 15 years of age should be given 6 months of IPT immediately after the successful completion of TB treatment1.
TST does not have a role in determining which child will benefit from IPT. TST can, however, be used to evaluate a child for active TB.
16.4.3 Health care workers with HIV
Long-term IPT (at least 36 months) is recommended for HIV-infected health workers known to be TST-positive, including those who convert from TST-negative to TST-positive.
Notes on IPT in HIV-infected individuals:
– All adults, adolescents, and children on IPT should be routinely given vitamin B6 in order to decrease the risk of peripheral neuropathy (pyridoxine PO: 10 mg daily).
– Before initiating IPT, it is important to assess for risk factors (viral hepatitis, chronic alcohol consumption, use of potentially hepatotoxic medication, etc.) and signs of liver disease. Baseline liver function tests (LFTs) should be considered in these cases and the benefit of IPT weighed against the potential risk that isoniazid might aggravate the liver disease. Routine monitoring of liver transaminases (ALT) is not necessary in all those taking IPT. LFTs should be considered only when clinically indicated and/or in those at significant risk for liver disease.
– If an adult or adolescent develops active TB while on IPT, a specimen should be sent for TB culture and drug susceptibility testing (DST). Adapted treatment (i.e. for drug-resistant TB) must be prescribed to those found to have active TB resistant to isoniazid.
– Children developing active TB while on IPT should be initiated on TB treatment that uses 4 drugs in the intensive phase (i.e. HRZE). If possible, perform culture and DST. It should be noted that the risk of a child developing drug-resistant TB in this scenario is much less compared to an adult.
A 3-month time lag allows any undiagnosed TB to be ‘unmasked’ by ART.
HIV-exposed infants are infants born to HIV-positive women (the infant is of unknown HIV infection status but may be HIV infected).
Contact is defined as living in the same household, or in close and regular contact with, any known or suspected TB case within the last 12 months.