The global HIV pandemic


  • What’s up with HIV laws in America? Great new video from @McClatchyDC #hivisnotacrime #HIVcriminalisation# 23 Nov 2015
  • UK: @Law_Commission scoping paper rejects expanding HIV/STI law to prosecute non-disclosure or potential exposure 09 Nov 2015
  • UK: No change to E&W HIV/STI criminalisation law/policy recommended by @Law_Commission pending a wider review. 09 Nov 2015
  • New @IAPAC guidelines to achieve 90-90-90 targets recommend ending HIV criminalisation. (Thanks @DrJoe1234 and team) 06 Nov 2015
  • Bahrain: New HIV-specific law would criminalise #HIV non-disclosure to ‘authorities, their partners or relatives’ 04 Nov 2015
  • #knowyourviralload Make routine #HIV viral load testing available to all @_ARASAcomms @ITPCglobal 29 Oct 2015
  • Where has the prevention benefit of treatment impacted #HIVcriminalisation in Europe? #EACS2015 #hivisnotacrime 28 Oct 2015
  • @KELINKenya, @ICWKenya, @ICW_Global Are you aware of this case? This woman needs a good defence lawyer 28 Oct 2015
  • This new report is a sobering and timely analysis of the state of funding for the human rights response to HIV.... 22 Oct 2015
  • Canada: New film explores the impact of using sexual assault law to prosecute HIV non-disclosure - See more at: 15 Oct 2015
  • US: Is Louisiana's 'AIDS exposure' statute outdated? Advocates say it adds to stigma #hivisnotacrime #criminalization 16 Sep 2015
  • Find out what's #insidethebox. Watch and share the short film “Inside The Box", #HIVisNOTaCRIME 14 Sep 2015
  • Thanks for the alert@strongthomas. Terribly irresponsible reporting@FM104Phoneshow. Shame on you! Talk to@HIVIreland for balanced reporting. 21 Aug 2015
  • Mexico: Veracruz state passses new law that criminalises ’wilful’ HIV transmission despite concerted advocacy efforts 10 Aug 2015
  • Canada: Majority of women with HIV who also inject drugs face legal obligation to disclose to sexual partners #HIVCan 28 Jul 2015
  • US: Missouri police, prosecutors, media reach new low in overly zealous policing of overly broad HIV criminalisation 22 Jul 2015
  • Turn It Up! an innovative resource by @TheSeroProject for US prisoners with HIV needs help reaching Kickstarter goal 21 Jul 2015
  • RT @KELINKenya: We are advocating for the immediate release of a TB Patient jailed in Narok for Interrupting treatment… 21 Jul 2015
  • RT @oronda: #TBisNotACrime campaign media briefing by @KELINKenya ahead of mention of case on 22 July,2015 @ Milimani High Court http://t.c… 21 Jul 2015
  • RT @oronda: Incarcerating TB patients beats the very purpose of taking them to prison if they are not in isolation #TBisNotACrime Cc. @KELI21 Jul 2015

The human immunodeficiency virus (HIV), first discovered in 1984, attacks the body’s immune system. If left undiagnosed and/or untreated, HIV can gradually weaken the immune system, making it more difficult for the infected person to fight off disease.

Acquired Immune Deficiency Syndrome (AIDS), first recognised in 1981, is the name for a collection of symptoms and illnesses that can occur if an HIV-positive person’s immune system becomes very weak as a result of HIV-related underlying immune deficiency. Since AIDS is not a disease, and because HIV infection does not inevitably lead to any one of these symptoms or illnesses, the term 'HIV-related illness' is now considered more accurate.

HIV is usually acquired in one of three ways:

  • through unprotected anal or vaginal sex.
  • from a mother to her baby.
  • through blood-to-blood contact, including sharing non-sterile drug-use equipment.

HIV infection most commonly occurs as a result of blood, semen, vaginal fluid, anal secretions or breast milk from a person with HIV entering another person’s body.

HIV exposure occurs when there is an opportunity for HIV to enter a person’s body, for example, through unprotected anal or vaginal sex. However, HIV is not easy to acquire. Whilst it is possible to be sexually exposed to HIV just once and become infected, it is very much more likely that this will be not the case. Some people are sexually exposed to HIV many hundreds of times and never become infected. Consequently, although most cases of HIV infection worldwide are attributable to sexual exposure, an act of sexual intercourse with an HIV-positive person is more likely than not to leave an HIV-negative person uninfected. Read more in the chapter: Risk.

Global HIV incidence – the number of new HIV infections per year – is now estimated to have peaked in 1996 with 3.5 million new infections per year.1 In 2008, the estimated number of new HIV infections was approximately 30% lower than at the epidemic’s peak 12 years earlier.1 The number of new infections appears to have stabilised in most regions of the world, although it is still increasing in Eastern Europe and Central Asia and in other parts of Asia.1

Worldwide, half of the estimated 33.4 million people living with HIV in 2008 were female1 and HIV is the leading cause of disease and death for women of childbearing age.2 Sub-Saharan Africa remains the global region most affected by HIV and AIDS – more than two-thirds of all people with HIV live in sub-Saharan Africa. In high-income countries with a low overall prevalence of HIV, sub-populations most affected by HIV include: gay men and other men who have sex with men; migrants; people who inject drugs; and sex workers.1

Researchers first succeeded in developing effective anti-HIV drugs in the mid-late 1990s. Combinations of these drugs, which are known collectively as antiretroviral therapy (ART), reduce levels of HIV in the blood and other bodily fluids, allowing the immune system to recover, and reducing the possibility of infectiousness. Most people who take ART on an ongoing basis are able to maintain good health for many years. ART is the standard of care for HIV treatment in wealthy countries, and is gradually becoming the standard of care in resource-limited countries. Read more in the chapter: Harm

Evidence-informed HIV prevention

The global number of people living with HIV is constantly increasing not only because people are continuing to acquire HIV, but also because effective treatment has resulted in significantly extended lifespans for people who have had timely access to HIV testing and counselling, and can access treatment and care.3,4,5,6,7

However, for every two people starting treatment another five are newly infected.1 Continued high rates of transmission of HIV largely result from a failure to use currently available, evidence-informed, effective prevention strategies and tools, and poor coverage of HIV-prevention programmes.8 Globally, less than one person in five at risk of acquiring HIV has access to basic HIV-prevention services.9

Three decades of experience have led to many evidence-informed HIV-prevention activities. These fall into the following broad categories.

Biomedical approaches

These include: male and female condoms; sterile drug-use equipment; male circumcision; and the use of ART to prevent infection in people exposed to HIV, known as post-exposure prophylaxis (PEP). Biomedical approaches currently being investigated include microbicides and novel uses of ART. Microbicides work like ‘invisible condoms’ creating a barrier to sexual transmission but, unlike condoms, are controlled by the receptive partner. ART may also be effective when taken by people at high risk of acquiring HIV. This is known as pre-exposure prophylaxis (PrEP).

ART's preventive effects are also being studied in populations that include people who are diagnosed with HIV and are taking treatment primarily for its health benefits. This is known as 'treatment as prevention'. Read more in the chapter: Risk

Individual approaches

These include voluntary counselling and testing for HIV antibodies (the 'HIV test'), and counselling to support people living with, and at risk of, HIV to help them reduce HIV-related risk behaviours. (See Supporting people living with HIV to protect themselves and others.)

Group and community approaches

These include sex education and HIV-related information in schools, as well as 'safer sex' and HIV-testing campaigns, and HIV-related information targeted at specific communities where HIV prevalence is higher than in the general population.

Socio-political and structural interventions

These include legal and policy interventions that may permit some of the other types of prevention work, such as condom distribution, provision of sterile drug-use equipment, or sex education in schools. Examples of structural interventions include reforming laws and policies, and strengthening their enforcement, in order to better address the drivers of vulnerability to HIV acquisition, such as gender inequality, violence, discrimination, economic inequality, and lack of social capital. (See also The role of the law in the global response to HIV.)


  1. UNAIDS and World Health Organization AIDS Epidemic Update. Joint United Nations Programme on HIV/AIDS (UNAIDS), Geneva. Available online at, 2009
  2. WHO Women and Health: Today's Evidence Tomorrow's Agenda. Geneva, available online at, 2009
  3. Nash D et al. Long-term immunologic response to antiretroviral therapy in low-income countries: a collaborative analysis of prospective studies. AIDS 12;22(17):2291-302, 2008
  4. Sanne IM et al. Long term outcomes of antiretroviral therapy in a large HIV/AIDS care clinic in urban South Africa: a prospective cohort study. J Int AIDS Soc 17;12:38, 2009
  5. Harrison KM et al. Life expectancy after HIV diagnosis based on national surveillance data from 25 states, United States. J Acquir Immune Defic Syndr, 53(1):124-30, 2010
  6. Lewden C and the Mortality Working Group of COHERE Time with CD4 count above 500 cells/mm3 allows HIV-infected men, but not women, to reach similar mortality rates to those of the general population: a 7-year analysis. Seventeenth Conference on Retroviruses and Opportunistic Infections, San Francisco, abstract 527, 2010
  7. Van Sighem A et al. Life expectancy of recently diagnosed asymptomatic HIV-infected patients approaches that of uninfected individuals. Seventeenth Conference on Retroviruses and Opportunistic Infections, San Francisco, abstract 526, 2010
  8. UNAIDS HIV Prevention, Date accessed: 13 April 2010
  9. World Health Organization Universal access by 2010., Date accessed: 14 April 2010
This content was checked for accuracy at the time it was written. It may have been superseded by more recent developments. NAM recommends checking whether this is the most current information when making decisions that may affect your health.