Human Immunodeficiency Virus: General Information
About Human Immunodeficiency Virus (HIV)
HIV attacks the body’s immune system, specifically the CD4 cells (T-cells), which help the immune system fight off infections. HIV can lead to acquired immunodeficiency syndrome (AIDS) if not treated. Untreated, HIV reduces the number of T-cells in the body, making the person more likely to get other infections. These opportunistic infections or cancers take advantage of a very weak immune system and signal that the person has AIDS, the last stage of HIV infection (2).
Symptoms
HIV typically progresses through 3 stages of disease (2):
Transmission
Only certain body fluids can transmit HIV—blood, semen, pre-seminal fluid, rectal fluids, vaginal fluids, and breast milk—from an infected person. These fluids must come in contact with a mucous membrane (found inside the rectum, vagina, penis, and mouth) or damaged tissue or be directly injected into the bloodstream (from a needle or syringe) for transmission to occur (2). HIV is NOT transmitted by air, water, saliva, sweat, tears, closed-mouth kissing, insects, pets, toilets, or sharing food and drinks.
Treatment
There is no cure for HIV, but it can be controlled with medical care. The medicine used to treat HIV is called anti-retroviral therapy or ART. If taken the right way this medicine can dramatically prolong the lives of most people with HIV and greatly lower their chance of infecting others. Before the introduction of ART in the mid-1990s, people with HIV could progress to AIDS in just a few years. Today, someone diagnosed with HIV, and treated before the disease is far advanced, can live nearly as long as someone who does not have HIV (2).
Prevalence and At-Risk Populations
According to the CDC, 39,782 people in the US received an HIV diagnosis in 2016. However, the annual number of new diagnoses has declined by 5% from 2011 to 2015 (2).
Here are more prevalence statistics from the CDC (2):
Prevention
Prevention strategies include abstinence (not having sex), limiting your number of sexual partners, never sharing needles, and using condoms the right way every time you have sex. Pre-exposure prophylaxis (PrEP) medication can be taken daily to prevent infection if you are at high risk for HIV or post-exposure prohylaxis (PEP) might be able to be take after being potentially exposed to HIV (2).
HIV attacks the body’s immune system, specifically the CD4 cells (T-cells), which help the immune system fight off infections. HIV can lead to acquired immunodeficiency syndrome (AIDS) if not treated. Untreated, HIV reduces the number of T-cells in the body, making the person more likely to get other infections. These opportunistic infections or cancers take advantage of a very weak immune system and signal that the person has AIDS, the last stage of HIV infection (2).
Symptoms
HIV typically progresses through 3 stages of disease (2):
- Stage 1: Acute HIV infection - Within 2 to 4 weeks after infection with HIV, people may experience a flu-like illness, which may last for a few weeks. This is the body’s natural response to infection. When people have acute HIV infection, they have a large amount of virus in their blood and are very contagious. But people with acute infection are often unaware that they’re infected because they may not feel sick right away or at all.
- Stage 2: Clinical latency (HIV inactivity or dormancy) - During this phase, HIV is still active, but reproduces at very low levels. People may not have any symptoms or get sick during this time. At the end of this phase, a person’s viral load starts to go up and the CD4 cell count begins to go down.
- Stage 3: Acquired immunodeficiency syndrome (AIDS) - AIDS is the most severe phase of HIV infection. People with AIDS have such badly damaged immune systems that they get an increasing number of severe illnesses, called opportunistic illnesses. Without treatment, people with AIDS typically survive about 3 years. Common symptoms of AIDS include chills, fever, sweats, swollen lymph glands, weakness, and weight loss. People are diagnosed with AIDS when their CD4 cell count drops below 200 cells/mm or if they develop certain opportunistic illnesses. People with AIDS can have a high viral load and be very infectious.
Transmission
Only certain body fluids can transmit HIV—blood, semen, pre-seminal fluid, rectal fluids, vaginal fluids, and breast milk—from an infected person. These fluids must come in contact with a mucous membrane (found inside the rectum, vagina, penis, and mouth) or damaged tissue or be directly injected into the bloodstream (from a needle or syringe) for transmission to occur (2). HIV is NOT transmitted by air, water, saliva, sweat, tears, closed-mouth kissing, insects, pets, toilets, or sharing food and drinks.
Treatment
There is no cure for HIV, but it can be controlled with medical care. The medicine used to treat HIV is called anti-retroviral therapy or ART. If taken the right way this medicine can dramatically prolong the lives of most people with HIV and greatly lower their chance of infecting others. Before the introduction of ART in the mid-1990s, people with HIV could progress to AIDS in just a few years. Today, someone diagnosed with HIV, and treated before the disease is far advanced, can live nearly as long as someone who does not have HIV (2).
Prevalence and At-Risk Populations
According to the CDC, 39,782 people in the US received an HIV diagnosis in 2016. However, the annual number of new diagnoses has declined by 5% from 2011 to 2015 (2).
Here are more prevalence statistics from the CDC (2):
- Gay and bisexual men bear the greatest burden by risk group, representing an estimated 26,200 of these new HIV infections.
- An estimated 1.1 million people in the United States were living with HIV at the end of 2015, the most recent year for which this information is available.
- Southern states accounted for 50% of new infections since 2014, due to lack of prevention and care strategies compared to other parts of the country (4).
- Young people aged 13-24 are especially affected by HIV. In 2015, they accounted for 22% of all new HIV diagnoses.
- Worldwide, there were about 1.8 million new cases of HIV in 2016. About 36.7 million people were living with HIV around the world in 2016, but only 19.5 million of them were receiving medicines to treat it. An estimated 1 million people died from AIDS-related illnesses in 2016.
- Sub-Saharan Africa bears the heaviest burden of HIV and AIDS worldwide, accounting for about 64% of all new HIV infections.
Prevention
Prevention strategies include abstinence (not having sex), limiting your number of sexual partners, never sharing needles, and using condoms the right way every time you have sex. Pre-exposure prophylaxis (PrEP) medication can be taken daily to prevent infection if you are at high risk for HIV or post-exposure prohylaxis (PEP) might be able to be take after being potentially exposed to HIV (2).
Historical and Modern Rise of HIV
Scientists identified a species of chimpanzee in Central Africa as the source of HIV infection in humans. The chimpanzee version of the immunodeficiency virus (called simian immunodeficiency virus, or SIV) was most likely transmitted to humans and mutated into HIV when humans hunted these chimpanzees for meat and came into contact with their infected blood (2). Studies show that HIV may have jumped from apes to humans as far back as the late 1800s. The earliest case of HIV was found in a blood sample of a man from the Democratic Republic of Congo (3).
Over decades, the virus slowly spread across Africa and into other parts of the world. We know that the virus has existed in the United States since at least the mid to late 1970s (2). Before the 1980s, researchers estimate that about 100,000 to 300,000 people were infected with HIV (3). By 1995, complications from AIDS was the leading cause of death for adults 25 to 44 years old. About 50,000 Americans died of AIDS-related causes. African-Americans made up 49 percent of AIDS-related deaths (3).
Death rates began to decline after multi-drug therapy became widely available. Azidothymidine was introduced in 1987 as the first treatment for HIV (3). In 1997, highly active antiretroviral therapy (HAART) became the new treatment standard. It caused a 47 percent decline in death rates. The number of deaths dropped from 38,780 in 1996 to 14,499 in 2000 (3).
HIV continues to be a major global public health issue. In 2016, an estimated 36.7 million people were living with HIV, with a global prevalence of 0.8% among adults (1). Despite the progress made across the 69 countries who witnessed a decline in new infections, UNAIDS warned that progress in combating viral transmission is still not happening fast enough to meet global targets (1). Some countries have achieved a decline of 50% or more in new HIV infections among adults over the last 10 years, while many have made no measurable progress.
Some countries are still experiencing increases in new HIV infections. Eastern Europe and central Asia is the only region in the world where the HIV epidemic continued to rise rapidly. Since 2010, the annual number of new infections in the Eastern Europe and Central Asia has climbed by 60%, with the Russian Federation (Russia) being the place of the largest epidemic (1). The epidemic is concentrated in key populations in this region, particularly people who inject drugs. There is also a lack of prevention programs and low access to treatments in these regions as well, leading to the increase (1).
Over decades, the virus slowly spread across Africa and into other parts of the world. We know that the virus has existed in the United States since at least the mid to late 1970s (2). Before the 1980s, researchers estimate that about 100,000 to 300,000 people were infected with HIV (3). By 1995, complications from AIDS was the leading cause of death for adults 25 to 44 years old. About 50,000 Americans died of AIDS-related causes. African-Americans made up 49 percent of AIDS-related deaths (3).
Death rates began to decline after multi-drug therapy became widely available. Azidothymidine was introduced in 1987 as the first treatment for HIV (3). In 1997, highly active antiretroviral therapy (HAART) became the new treatment standard. It caused a 47 percent decline in death rates. The number of deaths dropped from 38,780 in 1996 to 14,499 in 2000 (3).
HIV continues to be a major global public health issue. In 2016, an estimated 36.7 million people were living with HIV, with a global prevalence of 0.8% among adults (1). Despite the progress made across the 69 countries who witnessed a decline in new infections, UNAIDS warned that progress in combating viral transmission is still not happening fast enough to meet global targets (1). Some countries have achieved a decline of 50% or more in new HIV infections among adults over the last 10 years, while many have made no measurable progress.
Some countries are still experiencing increases in new HIV infections. Eastern Europe and central Asia is the only region in the world where the HIV epidemic continued to rise rapidly. Since 2010, the annual number of new infections in the Eastern Europe and Central Asia has climbed by 60%, with the Russian Federation (Russia) being the place of the largest epidemic (1). The epidemic is concentrated in key populations in this region, particularly people who inject drugs. There is also a lack of prevention programs and low access to treatments in these regions as well, leading to the increase (1).
Video ResourcesTED-Ed: Why it's so hard to cure HIV/AIDS
Janet Iwasa In 2008, something incredible happened: a man was cured of HIV. In over 70 million HIV cases, this was a first, and, so far, a last, and we don’t yet understand exactly how he was cured. But if we can cure people of various diseases, like malaria and hepatitis C, why can’t we cure HIV? Janet Iwasa examines the specific traits of the HIV virus that make it so difficult to cure. TED Talk: The Dangerous Evolution of HIV Edsel Salavana Think we're winning the battle against HIV? Maybe not, as the next wave of drug-resistant viruses arrives. In an eye-opening talk, TED Fellow Edsel Salvana describes the aggressive HIV subtype AE that's currently plaguing his home of the Philippines -- and warns us about what might become a global epidemic. |
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References
1. Global HIV and AIDS statistics. AVERT (2017). at <https://www.avert.org/global-hiv-and-aids-statistics>
2. HIV/AIDS | CDC. Cdc.gov (2018). at <https://www.cdc.gov/hiv/> accessed 24 February 2018.
3. Nall, R. The History of HIV. Healthline (2018). at <https://www.healthline.com/health/hiv-aids/history> accessed 24 February 2018.
4. U.S. Statistics. HIV.gov (2017). at <https://www.hiv.gov/hiv-basics/overview/data-and-trends/statistics> accessed 4 March 2018.
2. HIV/AIDS | CDC. Cdc.gov (2018). at <https://www.cdc.gov/hiv/> accessed 24 February 2018.
3. Nall, R. The History of HIV. Healthline (2018). at <https://www.healthline.com/health/hiv-aids/history> accessed 24 February 2018.
4. U.S. Statistics. HIV.gov (2017). at <https://www.hiv.gov/hiv-basics/overview/data-and-trends/statistics> accessed 4 March 2018.