Tuberculosis (TB) is caused by a germ called Mycobacterium tuberculosis that spreads from person to person when someone who is actively infected coughs or sneezes and you breathe in droplets contaminated with it. Not everyone who is exposed or infected gets sick with "active" TB, a disease that usually affects the lungs, causing coughing (for three weeks or longer), coughing up blood, and chest pain. Active TB can also affect the brain, kidneys or spine. Infected people who don't get sick are said to be living with latent tuberculosis. Fortunately, they cannot spread the infection to others. The only way you would know that you are living with latent tuberculosis is via testing: those affected usually will have a positive reaction to the tuberculin skin test or Quantiferon®-TB Gold test.
Between five to 10 percent of all people with latent TB eventually develop the active form and become capable of infecting others. About half the time, this happens within two years of infection. The risk is highest among those with weakened immune systems, particularly those with HIV. Some individuals with latent TB may be infected with extensively drug-resistant TB (xdr TB); this is bad news, since preventive treatment may not work.
Treating and eliminating latent TB is essential to controlling the spread of the disease since it ensures that those infected won't develop the active form and pass it on to others. I urge you to follow your physicians' recommendations. The treatment is safe; the danger of developing active TB and spreading it is greater than any risks of treatment.
However, I would recommend giving the babies milk thistle (Silybum marianum) to protect their livers during treatment. My colleague Tieraona Low Dog, M.D., director of education at the Arizona Center for Integrative Medicine at the University of Arizona, says that finding a standardized milk thistle extract in a form that infants can take may be difficult. The dose for a standardized extract in children is 5 to 10 mg per kilogram of body weight per day. The herb is quite safe, but because it can upset the stomach, start with a smaller dose and give it with food to see how your children respond. If you can't find a standardized extract in a usable form, Dr. Low Dog recommends using an alcohol-free milk thistle glycerite (a botanical products manufacturer called Eclectic Institute makes one). The dose would be ½ teaspoon twice a day for a two-year-old; start with half that for an infant.
Your children are fortunate that they can receive treatment. According to the World Health Organization, more than 250,000 children develop TB worldwide every year and 100,000 youngsters die from it annually.
Andrew Weil, M.D.