If you are healthy, you probably have a strong immune system and your body can fight off infections from bacteria or viruses easily. So if you breathe in TB bacteria, your immune system would probably kill them off straight away, without you ever getting ill or knowing about it.
But if you are run down or have another illness, your immune system might not be strong enough to fight the TB bacteria effectively. Stress, poor diet, certain medications, being pregnant or elderly can also weaken a person’s immune system.
Many different things can make your immune system weak, including:
- not getting enough fresh food and vitamins
- not sleeping enough
- working too hard or partying too much
- using drugs, drinking alcohol and smoking
- stress
- poor housing
- long-term illness, which affects your immune system – diabetes or HIV, for example
- certain prescription drugs – ask your doctor for advice
- being pregnant or elderly.
Having a weakened immune system doesn’t mean you will get TB. But it can make you more ‘open’ to the infection, especially if you spend time with someone who is coughing out TB bacteria.
TB and HIV
People living with HIV are much more likely than others to get ill with TB if they breathe in the bacteria. This is because HIV weakens their immune system, which makes it harder for the body to fight off infections. Having HIV also makes TB more difficult to diagnose and treat. Leaving a TB infection untreated speeds up the damage to a person’s health from HIV.
If you are diagnosed with TB, you can ask for an HIV test. Knowing you are HIV positive and have TB is important for you and for the people treating you. You can be treated for both infections at once and getting rid of TB will help your HIV medication work better.
If you are HIV positive you need to know the symptoms of TB. Also, ask for a TB test if you think you might have been in contact with someone with TB, even if you don’t have any symptoms.
Drugs and alcohol
Drinking, smoking, taking drugs and late nights can affect your immune system – so you can’t fight off infections as easily.
Smoking tobacco, cannabis and other drugs, such as crack and heroin, can also give you a cough. So you may think you just have a smoker’s or drug-related cough but this could be TB in your lungs. Keep an eye out for other symptoms of TB – such as night sweats. If you think you might have TB, see a doctor.
