World Aids Day is an opportunity for people worldwide to unite in the fight against HIV, show their support for people living with HIV and to commemorate people who have died.According to the World Health Organisation, HIV continues to be a major global public health issue and has so far claimed more than 34 million lives. READ MOREWorld Aids Day: 10 facts about the conditionHollywood actor Charlie Sheen’s high profile HIV interview with NBC’s Todayprogramme provided a timely reminder that the virus has not gone away.Globally, there were approximately 36.9 million people living with HIV at the end of 2014. In the UK, it is believed that as many as 18,000 people are unaware that they are living with HIV.18,000 The numer of people in the UK unaware they have HIVAdvances in medicine mean that contracting HIV no longer equals the certain death sentence it once suggested. However, the virus does still require careful management and life-long medication. Failing to take the precautions necessary for preventing HIV infection can also leave people vulnerable to other sexually transmitted infections (STIs) such as chlamydia, herpes or gonorrhoea. Even if you have no symptoms, it’s important to get yourself tested if you think you might be at risk of infection.What is HIV and AIDS?The Human Immunodeficiency Virus (HIV) causes an infection that can lead to acquired immunodeficiency syndrome, or AIDS.AIDS results in a progressive failure of the immune system leading to potentially fatal infections and cancers.How can HIV be passed on?HIV is carried by certain bodily fluids and can be passed on when those fluids are transferred from one person to another. Infected fluids need to pass into another person’s bloodstream for infection to occur.Those fluids include semen, breast milk and blood. HIV is not carried by saliva.