HUMAN IMMUNODEFICIENCY VIRUS (HIV) AND AIDS

HIV is a retrovirus that infects T helper lymphocytes, cells that co-ordinate the actions of other immune system cells and carry the CD4 receptor. Without treatment, over time the patient’s CD4 count declines, susceptibility to infections increases, symptoms develop, and become more severe until a diagnosis of AIDS (acquired immune deficiency syndrome) is made.

HIV is associated with significant mortality, serious morbidity and high costs of treatment and care. In the UK, around 100,000 people are living with HIV infection (diagnosed and undiagnosed) in the UK. The infection is still frequently regarded as stigmatising, and has a prolonged 'silent' period during which it often remains undiagnosed. 

Anti-retroviral therapy (ART) has resulted in substantial reductions in the number of people who progress to AIDS, and deaths in the UK. People who are diagnosed promptly and started on ART early can expect near normal life expectancy. The number of circulating viruses (viral load) predicts progression to late-stage HIV disease. 

HIV in pregnancy 

All pregnant women are recommended screening for HIV infection (as well as syphilis, hepatitis B and rubella) early in pregnancy. Approximately 2.5 per 1,000 pregnant women are HIV-positive, with most diagnosed before pregnancy. Interventions such as ART, elective caesarean section and avoidance of breastfeeding after delivery can reduce the rate of mother-to-child (vertical) transmission to less than 1%.