HIV/AIDS

The red ribbon is a symbol for solidarity with HIV-positive people and those living with AIDS.

HIV/AIDS, also known as HIV disease or HIV infection, is caused by the human immunodeficiency virus (HIV), a retrovirus that attacks the immune system. Without treatment, the infection can progress to acquired immunodeficiency syndrome (AIDS).

Early symptoms often resemble influenza, including fever and large lymph nodes, while later stages can lead to significant weight loss and complications such as opportunistic infections and tumours. The condition is lifelong but can be managed with antiretroviral therapy (ART), which significantly increases life expectancy and reduces the risk of transmission.

Signs and Symptoms

There are three main stages of HIV infection: acute infection, clinical latency, and AIDS.

Acute Infection

A diagram of a human torso labelled with the most common symptoms of an acute HIV infection

The initial period following HIV infection is called acute or primary HIV infection. Symptoms usually appear 2-4 weeks after exposure and can include fever, large tender lymph nodes, throat inflammation, rash, headache, tiredness, and sores of the mouth and genitals. These symptoms can last one or two weeks and are often mistaken for other common infections.

Clinical Latency

This stage, also known as asymptomatic HIV or chronic HIV, can last from about three years to over 20 years without treatment. Symptoms are generally few or absent initially but can include fever, weight loss, gastrointestinal problems, and muscle pains as the condition progresses. Persistent generalised lymphadenopathy is common, and a small proportion of individuals maintain high CD4+ T cell counts without ART.

AIDS

A diagram of a human torso labelled with the most common symptoms of AIDS

AIDS is defined as an HIV infection with a CD4+ T cell count below 200 cells per μL or the occurrence of specific diseases associated with HIV. Common initial conditions include pneumocystis pneumonia, HIV wasting syndrome, and esophageal candidiasis. Opportunistic infections and cancers such as Kaposi's sarcoma and Burkitt's lymphoma are more frequent in this stage.

Diagnosis

A generalised graph of the relationship between HIV copies (viral load) and CD4+ T cell counts over the average course of untreated HIV infection

HIV/AIDS is diagnosed through laboratory testing. Most people develop antibodies to HIV within three to twelve weeks after initial infection. Diagnosis before seroconversion is done by measuring HIV-RNA or p24 antigen. Positive results are confirmed by different antibody or PCR testing. Children under 18 months require PCR testing due to the presence of maternal antibodies.

Transmission

HIV is primarily spread through unprotected sexual contact, significant exposure to infected body fluids, and from mother to child during pregnancy, delivery, or breastfeeding. The virus cannot be transmitted through saliva, sweat, or tears unless contaminated with blood.

Prevention

People wearing AIDS awareness signs. On the left: "Facing AIDS a condom and a pill at a time"; on the right: "I am Facing AIDS because people I ♥ are infected"

Consistent condom use reduces the risk of transmission by approximately 80%. Male circumcision has been shown to reduce the acquisition of HIV by heterosexual men. Pre-exposure prophylaxis (PrEP) and post-exposure prophylaxis (PEP) with antiretroviral medications are effective preventive strategies. Preventive measures for mother-to-child transmission include antiviral medications during pregnancy and bottle feeding instead of breastfeeding.

Treatment

Stribild - a common once-daily ART regime

Stribild - a common once-daily ART regime consisting of elvitegravir, emtricitabine, tenofovir and the booster cobicistat

There is no cure or vaccine for HIV/AIDS, but ART can slow the progression of the disease. ART involves combinations of at least three medications from different classes of antiretroviral agents. Early and consistent treatment is recommended for all diagnosed individuals. Effective ART can reduce the viral load to undetectable levels, significantly reducing the risk of transmission and improving life expectancy.

Virology

Diagram of an HIV virion structure

HIV is a retrovirus that primarily infects CD4+ T cells, macrophages, and dendritic cells. The virus uses the host cell's machinery to replicate, leading to the destruction of CD4+ T cells and weakening the immune system. There are two types of HIV: HIV-1, which is more virulent and widespread, and HIV-2, which is less transmissible and largely confined to West Africa.

Self-assessment MCQs (single best answer)

What is the primary cause of HIV/AIDS?

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What is the main function of antiretroviral therapy (ART) for HIV/AIDS patients?

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Which of the following is NOT a common symptom of the acute HIV infection stage?

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What is the CD4+ T cell count threshold for diagnosing AIDS?

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Which of the following fluids is NOT a common medium for the transmission of HIV?

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What is the primary goal of pre-exposure prophylaxis (PrEP)?

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Which of the following is an opportunistic infection commonly associated with AIDS?

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In which stage of HIV infection is persistent generalised lymphadenopathy common?

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Which of the following is NOT a component of the common antiretroviral therapy regime Stribild?

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Which type of HIV is more virulent and widespread globally?

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