For how long is isoniazid typically administered for tuberculosis prophylaxis?

Isoniazid is typically administered for tuberculosis prophylaxis for a duration of 9 months. This treatment is recommended particularly for individuals who are at high risk of developing tuberculosis infection into active disease, such as those who have been recently exposed to someone with active TB, have positive tuberculin skin tests, or have weakened immune systems. The 9-month regimen has been shown to be effective in significantly reducing the risk of developing TB in these vulnerable populations.

Shorter or longer durations of treatment, such as 6 months or 12 months, do not provide the same level of efficacy in preventing the progression from latent infection to active disease as the established 9-month course. Additionally, the option that suggests never administering isoniazid for prophylaxis does not align with public health guidelines aimed at controlling TB spread. Thus, the choice of 9 months is grounded in clinical evidence and public health practices aimed at effectively preventing tuberculosis.