Tuberculosis and HIV.


Dear Dr Shearer.. I am 48 Year old Aussie having been diagnosed with hiv some 2 years ago and recently started medication which seems to be working very well.I recently met a man (Also HIV positve)who i have played around with several times..nothing to heavy (kissing and oral mostly)and I noticed he has been coughing a lot.I have met hm 3 times now and he just informed me via email that he has Tuberculosis and has had it for quite some time.What steps should i take to ensure that I havent contacted it..or is there even any risk? I would be most greatfull for your advice. Keep up the good work at the Body. Best Wishs...Chris W.


You should let your doctor know of this exposure right away, and together you can take the simple steps necessary to find out whether you acquired TB and now have a latent (subclinical) infection, whether you actually have an early stage of active TB disease (very unlikely), or whether you did not acquire the disease. You should be reassured that your risk is low, for a variety of reasons, and that you and your doctor can easily deal with the result of your investigations.

If your friend has had TB 'for some time' and known about it, it is likely that he has been diagnosed and treated, and, once effectively treated after 1-2 months, most people become non-infectious, although they still require prolonged treatment of 9 months or more. For this reason, your likely risk of exposure is quite low, but still worth investigating with your doctor.

We know from household contact data that your risk of acquiring TB is related to several factors, including the type of TB that your friend had, whether or not he was being treated at the time that you were together, the cumulative amount of time that you spent together, your own immune status at the time that you were together, and other factors. A person with TB is most infectious when they have cavitary pulmonary infection and are actively coughing.

You and your doctor can perform a simple Tuberculin Skin Test (TST), which is an intradermal injection of key particles from the Tubercle bacillus to which you will show a delayed hypersensitivity reaction - in the form of a 'wheal' or edema of >5mm - after 48 hours, IF you were infected. In some centers in the US, an alternate blood test is often performed, called an Interferon Gamma Release Assay (IGRA), that gives similar information to the TST.

Your doctor may also recommend that you have a chest xray, if you have not had one recently, in order to look for the possibility of sub-clinical active TB. And the other test that is routinely performed to look for TB is a smear and culture taken from your sputum, usually done on the first sputum in the morning over three days. You and your doctor can decide if that would be useful; as you did not mention any of the usual symptoms that we associate with TB, such as fever, chills, sweats, cough, and weight loss, this test is less likely to be useful, but you should be aware that people with HIV often have fewer signs and symptoms of TB than individuals who are not immune suppressed. You did not mention your current CD4 cell count, though you said that you were doing well on ART that was started recently. Your CD4 cell count is a factor in these issues as well.

If you have acquired the TB bacillus in your lung, but have not yet developed clinical disease, i.e. your chest xray is clear, you are considered to be latently infected, and you would benefit from treatment with anti-TB therapy, in addition to your ART.

If you have active TB and require 3 or 4 drug TB treatment, which is very unlikley, tt is possible that your doctor might recomend a different ART regimen in that event, because some ART medications have interactions or overlapping toxicities that make alternative medications more desirable. Here again, I want to reassure you that you and your doctor can readily cross that bridge in the unlikely event that it is necessary.

People with HIV have a more serious outcome if they have latent TB, because their risk of developing active TB at an average of 10% per year. In contrast, people with normal immune systems and latent TB infection have a 10% lifetime risk of developing active TB disease.

It is important to note, also, that a person with HIV infection may not have a positive TST or IGRA, even though they are latently infected, if they are severely immune suppressed, i.e. with CD4 cells below 100 cells/ml. For this reason, it is advised that HIV clinicians repeat a TST or IGRA in patients after they have had some immune recovery, because a previously negative TST or IGRA may turn positive in that circumstance.

So, in sum, be reassured that your risk of exposure is small. You and your doctor can perform some simple tests to find out whether or not an exposure took place and whether further steps, including TB treatment for latent TB infection or for active TB disease, are needed.