Interventions for Tuberculosis Control and Elimination 2002

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Figure 84. Tuberculosis risk and duration of intake of isoniazid preventive therapy
in the Bethel, Alaska, preventive chemotherapy studies. Reproduced from 896
by the permission of the publisher International Union Against Tuberculosis and Lung
Disease.
Prevention of disease with alternatives to isoniazid
Rifampicin has been remarkably effective in shortening the required duration
of chemotherapy of tuberculosis. 122,504 It is postulated to act particularly
well on mycobacterial sub-populations with only short bursts of metabolic
activity. 456 Such a situation probably exists in the case of latent
tuberculous infection and it is thus appealing to hypothesize that rifampicin
might be effective in preventive chemotherapy and may also reduce the
duration of the required treatment period compared to isoniazid.
In a mouse model, Lecoeur and collaborators tested the efficacy of
rifampicin with or without other drugs in combination as a preventive
chemotherapy tool in comparison with isoniazid. 900
Latent, sub-clinical infection was produced by vaccination with BCG
and subsequent challenge with M. tuberculosis. After an initial increase in
viable tubercle bacilli, this produced a stable count of bacilli in the spleen,
indicating that the relatively limited population was no longer actively multiplying
in the spleen when drug treatment was given. In a first experi-
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