Expert: Gary - 4/21/2005

Question
I wonder if you have an idea about how long a healthy person could go without knowing they had TB after being exposed to it? Could it possibly be a year or so? Also, would some of the symptoms be tiredness, weakness weight loss?
Thanks

Answer
Hi Betty

Thanks for your question. Firstly, it's important to remember that "TB infection" and "TB disease" are different. TB infection is where the TB bacteria have entered your body but you don't know about it and you don't feel unwell because you don't have "disease". In other words your body's immune system dealt with the problem as soon as the TB bacteria entered. Your immune system may not kill the TB bacteria entirely but it makes them go to sleep so they can't harm you (this is referred to as "latent" or "dormant" TB infection). In fact, this is what happens in the vast majority of cases and, in fact, only about 5% of people actually develop TB "disease" straight away (well within a few months) after becoming "infected". It is estimated that a third of the world's population has TB "infection"!!!

Most people who have been "infected" with TB DO NOT develop "disease". They simply live a long and perfectly normal life and eventually die at a ripe old age of something completely unrelated and they never knew they had TB infection. In a few, however, the "infection" does develop into "disease" and that's when they get symptoms (people who only have "infection" don't get symptoms). This can happen for a number of reasons. One of the main reasons that the "infection" develops into "disease" is because the person's immune system gets weak and, as you may know, this can happen for many, many reasons. Getting old is one reason because the immune system wane's as we get older so it is less able to keep those TB bacteria dormant and they burst back to life and cause disease.

So, to answer your question... a healthy person can live an entire life without knowing they have been infected with TB.  Remember too, that most people who get exposed to TB in their normal day-to-day life in countries like the UK (I'm not sure where you live) do NOT become infected. If an "infected" person DOES develop TB "disease" it can happen at any time after the infection occured, years or even decades later. The symptoms you mention can be experienced when someone has TB BUT they can also be caused by other things. Some people are at a higher risk of getting TB than others and most doctors and nurses know what these risk factors are. They also know what to look for in terms of symptoms and other possible causes for these symptoms.

My advice would be to see your doctor or nurse if the symptoms you describe do not disappear after about 2 weeks.

Remember too that TB can be cured these days so don't be too worried if that is what's wrong with you, but make sure you follow your doctor's instructions for taking any medicines properly.

Hope this helps

All the best

Gary