Underactive Immune System
To work properly, your immune system needs to be able to tell the difference between ‘good’ cells (your own healthy cells) and ‘bad’ cells (bugs, human cells infected with viruses or cancer cells). If you have a weakened immune system, it will not recognise or fight the ‘bad’ cells as well as it should. This means that you are more likely to get infections or to develop cancer. Examples of situations where your immune system is underactive include people suffering HIV/AIDS, people taking immune suppressing drugs to allow an organ transplant (e.g. a kidney transplant) or people taking long-term steroids to treat diseases e.g. chronic bronchitis.