HIV facts

When caring for someone with HIV, make sure you know the facts about this disease.

Facts about HIV

  • HIV stands for Human Immunodeficiency Virus. This name describes how the virus attacks and destroys the body’s natural defensive mechanism, exposing the body to certain infections.
  • HIV can be found in blood, the rectal mucosa, semen and seminal fluids, vaginal fluids and breast milk. The amount of virus that is present in those tissues is enough to infect a person. Whilst HIV can also be found in sweat and saliva, the amount is too small for an infection to happen.
  • Even without treatment, people with HIV may be well and without symptoms for a prolonged period of time, while the virus acts slowly to weaken the body’s immune system. HIV particularly attacks certain white blood cells called CD4 cells. CD4 cell count provides a good indication of the status of the immune system. Generally, when the CD4 count is very low the body’s immune system is very weak.
  • The continued effect of HIV on the body and the destruction of  a person’s immune system makes them more susceptible to other illnesses, especially some kind of infections (e.g. tuberculosis and pneumonia) and cancers, many of which are not normally a threat to a healthy person.
  • When the immune system of a person has reached a certain low level of CD4 cells, or when some of those associated infections have happened, then it is appropriate to talk about AIDS. AIDS stands for Acquired Immunodeficiency Syndrome and highlights a stage during the course of infection with HIV. As different associated infections may present with different symptoms, scientists have been updating the definition of what constitutes AIDS see Centers for Disease Control definition; also World Health Organization. 1987 revision of CDC/WHO case definition for AIDS. Wkly Epidemiol Rec 1988; 63: 1-7; Ancelle-Park R. Expanded European AIDS case definition. Lancet 1993; 341: 441)
  • As AIDS is one of the stages of the infection caused by HIV, it is not correct to talk about ‘passing AIDS’, ‘the AIDS virus’ or ‘being infected with AIDS’.

How HIV is transmitted

  • HIV is transmitted from an infected person through the transfer of body fluids such as blood, semen and seminal fluids, vaginal fluids and breast milk.
  • It can be transmitted by having sexual intercourse (oral, vaginal, anal) without a condom with a partner infected with HIV.
  • HIV is not passed on through everyday social contact with an infected person. Touching, shaking hands, hugging, coughing or sneezing cannot pass on the virus.
  • Transmission from mother to babies can happen during pregnancy, childbirth or breastfeeding. In the UK, the introduction of universal, ‘opt-out’ HIV testing for pregnant women, among other measures, has reduced the risk of mother to child transmission to well under 3%.
  • Transmission can also occur when the blood of an HIV-positive person gets in contact with the blood of an HIV-negative person. This can happen when injecting drug users share needles or other equipment; if needles or syringes are re-used or if surgical and dental instruments have not been adequately sterilized; if a person receives a transfusion of blood or blood products contaminated with HIV; and finally, through tattoos and piercing practices (though this is much less likely). 
  • Although the risk of acquiring HIV for healthcare workers following an occupational exposure (for example a needlestick) is small (around 0.3%, according to the Health Protection Agency), it is essential that all healthcare workers follow their local protocols and national guidelines to prevent and manage accidental exposures to HIV. More information is available in Standard precautions.

Epidemiology

It is important to be familiar with the number and characteristics of the people infected and living with HIV in the UK and in your local area. The Health Protection Agency is the public health surveillance body that produces reports on the epidemiology of HIV in England and Wales.

  • In 2006, there were an estimated 73,000 persons living with HIV in the UK (aged 15-59). This figure includes both those who have been diagnosed and also people who remain unaware of their infection (around a third of all diagnoses).
  • In the UK some individuals are at higher risk of infection than others, but every person should be individually assessed. The groups with higher infection prevalence are:
    • Men who have sex with men, who are proportionally the group at greatest risk of HIV infection (43% of all cases were diagnosed in this group)
    • Heterosexual women (31% of all cases) and men (21% of cases). African-born men and women accounted for over a third (35%) of the total number of adult cases. However, if we only consider the infections acquired heterosexually, African-born women and men accounted for 68% of the total
    • And injecting drug users (4% of cases)
  • The frequency of HIV is increasing in older age groups. For example, the number of HIV-infected adults (55 years or over) who accessed care between 1997 and 2006 increased from 658 to 3,965. These older persons now account for 7.6% of all HIV-infected persons accessing care in 2006. Increased life expectancy and new infections in these age groups are fuelling this growing trend.
  • In terms of geographical distribution, whilst London remains the main focus of care for people living with HIV, with nearly 24,000 residents accessing HIV-related care, the largest proportional increase was seen in Yorkshire and the Humber where there were 2,475 people accessing treatment in 2006 - a 21% increase.
  • There is room for improvement in the role that nurses can play in ensuring that people with symptoms or illnesses suggestive of HIV infection get offered a test. 33% (2,281) of newly diagnosed cases had a CD4 cell count below 200 cells/mm3 within 30 days of HIV diagnosis, thus remaining less likely to benefit from therapy and being at an increased risk of dying as a result.

For more information, please download the annual report from the Health Protection Agency (HPA) ‘Testing Times - HIV and other Sexually Transmitted Infections in the United Kingdom: 2007' (PDF 4.6MB) [see How to access PDF files].