HIV / AIDS

This article was first published in November 2014; last revised in November 2019.

HIV (human immunodeficiency virus) is a lentivirus which can lead to acquired immunodeficiency syndrome (AIDS). AIDS in humans results in a gradual and persistent decline and failure of the immune system, resulting in heightened risk of life-threatening infection and cancers.

In the majority of cases, HIV is a sexually-transmitted infection. However, HIV can also be transmitted from a mother to her child, during pregnancy or childbirth (through blood or fluid exposure), or through breastfeeding. Non-sexual transmission can also occur through the sharing of injection equipment such as needles.

HIV/AIDS is one of the world’s most fatal infectious diseases

Almost 1 million people die from HIV/AIDS each year; in some countries it’s the leading cause of death

HIV/AIDS is one of the world’s most fatal infectious diseases – particularly across Sub-Saharan Africa, where the disease has had a massive impact on health outcomes and life expectancy in recent decades.

The Global Burden of Disease is a major global study on the causes of death and disease published in the medical journal The Lancet.1 These estimates of the annual number of deaths by cause are shown here. This chart is shown for the global total, but can be explored for any country or region using the “change country” toggle.

In the chart we see that, globally, it is the second most fatal infectious disease.

According to the Global Burden of Disease study, almost one million (954,000) people died from HIV/AIDS in 2017. To put this into context: this was just over 50% higher than the number of deaths from malaria in 2017.

It’s one of the largest killers globally; but for some countries – particularly across Sub-Saharan Africa, it’s the leading cause of death. If we look at the breakdown for South Africa, Botswana or Mozambique – which you can do on the interactive chart – we see that HIV/AIDS tops the list. For countries in Southern Sub-Saharan Africa, deaths from HIV/AIDS are more than 50% higher than deaths from heart disease, and more than twice that of cancer deaths.

The global distribution of deaths from HIV/AIDS

In some countries HIV/AIDS is the cause of more than 1-in-4 deaths

Globally, 1.7% of deaths were caused by HIV/AIDS in 2017.

This share is high, but masks the wide variations in the toll of HIV/AIDS across the world. In some countries, this share was much higher.

In the interactive map we see the share of deaths which resulted from HIV/AIDS across the world. Across most regions the share was low: across Europe, for example, it accounted for less than 0.1% of deaths.

But across some countries – focused primarily in Southern Sub-Saharan Africa – the share is very high. More than 1-in-4 of deaths (28%) in South Africa and Botswana were caused by HIV/AIDS in 2017. The share was also very high across Mozambique (24%); Namibia (23%); Zambia (18%); Kenya (17%); and Congo (15%).

Death rates are high across Sub-Saharan Africa

The large health burden of HIV/AIDS across Sub-Saharan Africa is also reflected in death rates. Death rates measure the number of deaths from HIV/AIDS per 100,000 individuals in a country or region.

In the interactive map we see the distribution of death rates across the world. Most countries have a rate of less than 10 deaths per 100,000 – often much lower, below 5 per 100,000. Across Europe the death rate is less than one per 100,000.

Across Sub-Saharan Africa the rates are much higher. Most countries in the South of the region had rates greater than 100 per 100,000. In South Africa and Mozambique, it was over 200 per 100,000.

Death rates are highest for younger adults and children under five years old

Which population groups are most at risk from HIV/AIDS?

In the chart we show death rates by age group. Here we see that the group most at risk are 15 to 49 year olds – typically younger adults. Since HIV is primarily a sexually-transmitted infection, where unsafe sex is a primary risk factor, this is what we would expect.

But we also see that death rates are higher for young children under five years old. This is because HIV can be transmitted from mother-to-child if the mother is infected.

How have deaths from HIV/AIDS changed over time?

Global deaths from HIV/AIDS halved within a decade

The world has made significant progress against HIV/AIDS. Global deaths from AIDS have halved over the past decade.

In the visualization we see the global number of deaths from HIV/AIDS in recent decades – this is shown by age group. In the early 2000s – 2004 to 2005 – global deaths reached their peak at almost 2 million per year.

Driven mostly by the development and availability of antiretroviral therapy (ART), global deaths have halved since then. In 2017, just under one million died from the disease.

You can explore this change for any country or region using the “change country” toggle on the interactive chart.

HIV/AIDS once accounted for more than 1-in-3 deaths in some countries, but rates are now falling

Global progress on HIV/AIDS has been driven by large improvements in countries which were most affected by the HIV epidemic.

Today the share of deaths remains high: more than 1-in-4 deaths in some countries are caused by HIV/AIDS. But in the past this share was even higher.

In the visualization we see the change in the share of deaths from HIV/AIDS over time. From the 1990s through to the early 2000s, it was the cause of greater than 1-in-3 deaths in several countries. In Zimbabwe, it accounted for more than half of annual deaths in the late 1990s.

We see that over the past decade this share has fallen as antiretoviral treatment has become more widely available.

HIV/AIDS has had a major impact on life expectancy across Sub-Saharan Africa

The health and mortality burden of HIV/AIDS across Sub-Saharan Africa has been large: we see this when we look at the share of deaths caused by the disease.

We see this impact on health reflected in trends in life expectancy. In the visualization we show changes in life expectancy across select countries in Sub-Saharan Africa for which HIV/AIDS has had the largest toll.

We see a dramatic drop in life expectancy around 1990 – which coincides with the rise of HIV. In Bostwana, life expectancy fell by a decade; in Swaziland it fell by two decades. Since the early 2000s – as progress has been made on tackling HIV – we see that life expectancy has been rising again.

But life expectancy is only now approaching levels prior to the HIV epidemic.

The prevalence of HIV/AIDS

Prevalence in the total population

Share of the population with HIV

You can explore the total number of people living with HIV/AIDS across the world here.

Number of new infections each year

Prevalence by gender

Is HIV/AIDS more common in men or women?

There are differences in both the prevalence of HIV and death rates from AIDS between men and women. The chart shows the share of women in populations living with HIV.

As we see, HIV prevalence tends to be higher in women across Sub-Saharan Africa, although higher in males across most other regions. The trend in AIDS-related deaths shows the opposite: more men tend to to die from AIDS every year than women. The reasons for differences in prevalence and death rates are complex; however, in general, across Sub-Saharan Africa women tend to be infected with HIV earlier than men and survive longer (explaining both the higher prevalence and lower annual AIDS deaths in women). There are a number of gender inequality and social norm issues which result in higher prevalence of HIV in females across many countries; women are at greater risk when they have a limited role in sexual decision-making and protection, role rates of sexual education and higher rates of transactional sex2.

Prevalence in children

Share of children infected with HIV

Children living with HIV

In children with HIV, transmission has typically occurred from the mother (mother-to-child-transmission; MTCT) either during pregnancy or childbirth, or through breastfeeding. The chart shows the total number of children aged 14 years old and under who are living with HIV. Globally the number of children living with HIV peaked in 2005 at approximately 2.1 million. This has since declined to 1.8 million in 2017.

New HIV infections of children

The map shows the total number of children newly infected with HIV each year. Globally — with similar trends at national levels — the number of new infections in children peaked around the early 2000s (globally at 420,000 new infections per year) followed by a rapid decline over the last decade. In 2017 an estimated 180,000 new children were infected with HIV.

Orphaned children from AIDS

‘Orphaned’ children are defined as those who have lost either one or both parents from AIDS. This does not necessarily imply that children orphaned by AIDS have HIV themselves (although in some cases HIV has been transmitted from mother-to-child). The chart shows the number of children (aged 17 and under) orphaned from AIDS deaths.

Tuberculosis among People Living with HIV

Tuberculosis (TB) is the leading HIV-associated opportunistic infection in low- and middle- income countries, and it is a leading cause of death globally among people living with HIV. Death due to tuberculosis still remains high among people living with HIV, however the number of deaths is decreasing. Most of the global mortality due to TB among those with HIV is from cases in Sub-Saharan Africa.

In the charts here we see the number of tuberculosis (TB) patients who tested positive for HIV; the number receiving antiretroviral therapy (ART); and the number of TB-related deaths among those living with HIV.

What can be done to prevent HIV/AIDS?

Anti-retroviral treatment (ART)

Reducing the impact of the HIV epidemic requires the prevention of further transmission, as well as treatment for those already living with HIV. Antiretroviral therapy (ART) is highly active in suppressing viral replication, reducing the amount of the virus in the blood to undetectable levels and slowing the progress of HIV disease.

The chart shows the share of people with HIV receiving antiretroviral therapy (ART).

ART averts more than 1 million deaths each year

Antiretroviral therapy (ART) has been critical in reducing the number of deaths from AIDS.

In the visualization here we see the number of deaths from AIDS, as well as the number of deaths averted as a result of ART. Globally, 1.2 million deaths in 2016 were averted as a result of ART – this is greater than the 1 million deaths which occurred. Without ART, global deaths from AIDS would be more than double their current annual figures.

In South Africa, ART has been crucial in reducing death rates from AIDS. Approximately three-quarters of potential deaths from AIDS were averted in 2016 as a result of ART.

You can explore the number of deaths averted from antiretroviral treatment across the world here.

Improved coverage of ART is needed

Prevention of mother-to-child transmission (PMTCT)

Given that majority of AIDS cases in children are due to the virus transmission from mother to child during pregnancy, stopping the mother-to-child transmission is key to preventing children from getting newly infected with HIV.

The chances of HIV positive mother transmitting the virus to a child are between 15% and 45%. Effective prevention of mother-to-child transmission (PMTCT) services can reduce the chances of virus transmission to newborn to 5%.3

PMTCT services include preventative measures such as providing antiviral therapy for mother and newborn, correct breastfeeding practices, and early child testing for HIV infection.

The visualization shows the number of child infections averted from coverage of ART in mothers.

You can explore the number of new HIV infections prevented from PMTCT as a result of antiretroviral therapy across the world, here.

Coverage of ART in pregnant women

In this map we see the share of pregnant women infected with HIV who receive antiretroviral therapy – a vital intervention to prevent the transmission from mother-to-child.

Safe sex

Unsafe sex is a leading risk factor for death in Sub-Saharan Africa

Share of people practicing safe sex

The majority of HIV infections are transmitted through sexual activity.

Sexual transmission can be prevented through condom use (both in heterosexual and homosexual relationships). In the charts here we see the prevalence of condom use, particularly in cases of ‘high-risk sex’, which is that with a non-marital, non-cohabiting sexual partner.

Education on HIV/AIDS

Funding to support efforts against HIV/AIDS

You can explore the breakdown of funding resources by source, for each country, here.

Future funding needs to meet HIV targets

Increased funding is needed to meet global HIV targets by 2030

Data Quality & Definition

Terminology and Definitions

The following terminology and definitions are sourced from the UNAIDS organization.4

HIV: Human Immunodeficiency Virus. HIV is a virus that weakens the immune system, ultimately leading to AIDS.

AIDS: acquired immunodeficiency syndrome.

Antiretroviral medicines/ Antiretrovirals (ARVs)/ Antiretroviral therapy (ART)/ HIV treatment: “Antiretroviral therapy is highly active in suppressing viral replication, reducing the amount of the virus in the blood to undetectable levels and slowing the progress of HIV disease. The usual antiretroviral therapy regimen combines three or more different medicines, such as two nucleoside reverse transcriptase inhibitors (NRTI) and a protease inhibitor, two nucleoside analogue reverse transcriptase inhibitors and a non-nucleoside reverse transcriptase inhibitor (NNRTI), or other combinations.

More recently, entry inhibitors and integrase inhibitors have joined the range of treatment options. Suboptimal regimens are monotherapy and dual therapy. The term highly active antiretroviral therapy was commonly used after the demonstration of excellent virological and clinical response to combinations of three (or more) antiretroviral medicines. Highly active is not needed as a qualification, however, and the term is no longer commonly used.

ARV refers to antiretroviral medicines. It should only be used when referring to the medicines themselves and not to their use.”

ARV-based prevention: “ARV-based prevention includes the oral or topical use of antiretroviral medicines to prevent the acquisition of HIV in HIV-negative persons (such as the use of pre-exposure prophylaxis or post-exposure prophylaxis) or to reduce the transmission of HIV from people living with HIV (treatment as prevention).”

Epidemic: “An epidemic refers to a disease condition affecting (or tending to affect) a disproportionately large number of individuals within a population, community or region at the same time. The population may be all of the inhabitants of a given geographic area, the population of a school or similar institution or everyone of a certain age or sex (such as the children or women of a region). An epidemic may be restricted to one locale (an outbreak), be more general (an epidemic) or be global (a pandemic). Common diseases that occur at a constant but relatively high rate in the population are said to be endemic.”

HIV-negative (seronegative): “A person who is HIV-negative (also known as seronegative) shows no evidence of HIV in a blood test (e.g. there is an absence of antibodies against HIV). The test result of a person who has acquired HIV but is in the window period between HIV exposure and detection of antibodies also will be negative.”

HIV-positive (seropositive): “A person who is HIV-positive (or seropositive) has had antibodies against HIV detected in a blood test or gingival exudate test (commonly known as a saliva test). Results may occasionally be false-positive, especially in infants up to 18 months of age who are carrying maternal antibodies.”

Incidence: “HIV incidence is expressed as the number of new HIV infections over the number of people susceptible to infection in a specified time period. Cumulative incidence may be expressed as the number of new cases arising in a given period in a specified population. UNAIDS reports the estimated number of incident cases that occurred in the past year among people aged 15–49 years and 0–14 years.”

Mother-to-child transmission (MTCT): “MTCT is the abbreviation for mother-to-child transmission. PMTCT, the abbreviation for prevention of mother-to-child transmission, refers to a four-prong strategy for stopping new HIV infections among children and keeping their mothers alive and families healthy. The four prongs are: helping reproductive-age women avoid HIV (prong 1); reducing unmet need for family planning (prong 2); providing antiretroviral medicine prophylaxis to prevent HIV transmission during pregnancy, labour and delivery, and breastfeeding (prong 3); and providing care, treatment and support for mothers and their families (prong 4).

PMTCT often is mistakenly used to refer to only prong 3— the provision of antiretroviral medicine prophylaxis. Some countries prefer to use the terms parent-to-child transmission or vertical transmission as more inclusive terms to avoid stigmatizing pregnant women, to acknowledge the role of the father/male sexual partner in transmitting HIV to the woman and to encourage male involvement in HIV prevention. Still other countries and organizations use the term elimination of mother-to-child transmission (eMTCT).”

Prevalence: “Usually given as a percentage, HIV prevalence quantifies the proportion of individuals in a population who are living with HIV at a specific point in time. HIV prevalence also can refer to the number of people living with HIV. UNAIDS normally reports HIV prevalence among people aged 15–49 years.”

Tuberculosis (TB): “Tuberculosis (TB) is the leading HIV-associated opportunistic infection in low- and middle- income countries, and it is a leading cause of death globally among people living with HIV. The term HIV-associated tuberculosis or HIV-associated TB should be used, rather than the shorthand HIV/TB, in order to distinguish such instances from tuberculosis per se.

The main strategies to reduce the burden of HIV in TB patients are HIV testing (for people whose HIV status is unknown) and the provision of antiretroviral therapy and cotrimoxazole preventive therapy (CPT) (for people living with HIV). The main activities to reduce TB among people living with HIV are regular screening for TB among people in HIV care and the provision of isoniazid preventive therapy (IPT) and ART to HIV-positive people without active TB who meet eligibility criteria.”

Comparisons of UNAIDS and IHME estimates

A number of sources publish estimates on HIV and AIDS – two of the most established (which are presented in this entry) are UNAIDS and the Institute of Health Metrics and Evaluation (IHME), Global Burden of Disease. In the charts below we show the relationship/consistency in estimates of prevalence between these two sources.

Prevalence of HIV

Incidence/new cases of HIV

Data Sources

Joint United Nations Program on HIV and AIDS (UNAIDS)
  • Data: Data on size of epidemic and response
  • Geographical coverage: Global
  • Time span: 1990-2014
  • Available at: Online here
  • There are also tools to analyze the data online, and there is background information on the data and the disease.
World Health Organization
  • Data: Data on size of epidemic and response
  • Geographical coverage: WHO member nations
  • Time span: Since c. 2001
  • Available at: The WHO publishes data here.
Institute of Health Metrics and Evaluation (IHME), Global Burden of Disease (GBD)
  • Data: Death rates & absolute number of deaths from HIV/AIDS
  • Geographical coverage:Global, across all regions and countries
  • Time span:Available from 1990 onwards
  • Available at: Online here
Gapminder
  • Data: HIV/AIDS prevalence and mortality
  • Geographical coverage: Global
  • Time span: Mostly 1990-2011, but some data goes back as far as 1980
  • Available at: Here are data on the share of adults with AIDS.
  • Gapminder also published an extensive documentation of their data, which is online here.
USAID Demographic and Health Surveys
  • Data: Survey data
  • Geographical coverage: Global
  • Time span: Since the 1980s for some countries
  • Available at: Online here
United States Census Bureau in partnership with USAID
  • Data: Data on prevalence and incidence
  • Geographical coverage: Global
  • Time span: Since 1980s for some countries
  • Available at: Online here