Should tuberculosis (TB)-preventive therapy (IPT) be given to all?

By Bobby Ramakant, CNS
August 3, 2010
The author is a CNS Policy Adviser and Director of CNS Stop-TB Initiative. He is a World Health Organization (WHO) Director-General’s WNTD Awardee (2008) and writes extensively on health and development for Citizen News Service (CNS). Website: www.citizen-news.org, email: bobby@citizen-news.org

(CNS): A raging issue on the first day of XVIII International AIDS Conference was whether Isoniazid (INH) Preventive Therapy (IPT) be given to all –regardless whether people have TB or not? A full-course of IPT can prevent latent tuberculosis (TB) infection from becoming active TB disease. It is very crucial and often life-saving for people living with HIV (PLHIV) who are co-infected with tuberculosis (TB) as TB continues to be the biggest killer of PLHIV.

The World Health Organisation (WHO) guidelines recommend that IPT should be given only to those people who are confirmed to have latent TB (and NOT active TB disease).

Dr Jonathan E Golub, Assistant Professor at John Hopkins’ Centre for Tuberculosis Research said that IPT has been recommended for PLHIV for over 10 years, but the uptake is so poor.

Dr Golub suggested that putting all patients, without waiting for confirmatory tuberculin skin test (TST) for TB, should be put on IPT. He said, the concerns if we do this are:

- it may potentially make people who have active TB disease, resistant to one of the most powerful anti-TB drug – isoniazid/ INH (instead of preventing TB disease) – Dr Jonathan remarked that most studies have shown that resistance to INH is low so if we see the benefits of putting all PLHIV on IPT and preventing active TB disease in a large number of them, then these benefits might outweigh the concerns of low resistance to INH reported by few

- Toxicity to isoniazid (INH): A delegate raised this concern that patients with active TB disease will suffer toxicity to INH without any benefit, rather may develop resistance Dr Jonathan responded that in most studies he is aware of, toxicity to INH is low

- Overtreatment of those who have neither – latent or active TB disease! Dr Jonathan said this outweighs the benefits of protecting a significant number of PLHIV in high burden countries from getting active TB disease

Dr Jonathan said that benefits of putting all PLHIV on IPT, outweighs these concerns. Meantime the doctors can wait for TST results that take a long time to come, and meantime many PLHIV reported to have contracted active TB disease already! So preventing active TB infections, for PLHIV, is so crucial, and a big outcome of this option – to put all people on IPT regardless of their TB status.

The funding for the research Dr Jonathan conducted in Brazil came from the Bill & Melinda Gates Foundation, Fogarty International Centre and the NIAID.

Preventing active-TB disease is undoubtedly an under-invested intervention with 1/3rd global population estimated to have latent TB. Such therapy can protect these people from developing active TB disease, due to compromised immunity or any such reason. (CNS)

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Posted on: August 04, 2010 08:41 AM IST