Summary

Human Immunodeficiency Virus (HIV) is a virus that attacks the body's immune system, specifically the CD4 cells (T cells), which are crucial for fighting off infections and diseases. If not properly managed, HIV can lead to Acquired Immunodeficiency Syndrome (AIDS), the most severe stage of HIV infection where the immune system is so compromised that it can't fight off common infections and diseases.

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Introduction

Human Immunodeficiency Virus (HIV) is believed to have originated from the transfer of the Simian Immunodeficiency Virus (SIV) from chimpanzees and other monkeys to humans in Central Africa. Over time, the virus gradually mutated to become HIV as we know it today.^[1]

There are two types: HIV-1 and HIV-2, where HIV-1 is the common strain worldwide. HIV is primarily transmitted through direct contact with certain bodily fluids of an infected person, such as blood, semen, vaginal and rectal fluids, and breast milk. This transmission can happen through sexual behavior, sharing of injection drug equipment, or from mother to child during birth or breastfeeding. To reduce the stigma around HIV, it is essential to understand the virus cannot spread through saliva, sweat, tears, casual contact, swimming pools, etc. 

The disease progression varies among individuals. Some people may not show symptoms for many years, while others may develop symptoms soon after infection. Early-stage symptoms can include flu-like symptoms, and later-stage symptoms can be more serious, such as rapid weight loss, recurring fever, prolonged swelling of lymph glands, and others.

While there is currently no cure for HIV, antiretroviral therapy (ART) can control the virus and prevent transmission. With proper medical care, HIV can be managed as a chronic disease, and individuals with HIV can lead a healthy life for many years and even have an expected lifespan. Regular testing and early detection of HIV are key to managing the disease effectively.^[2-4]

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Possible Test Results 

HIV is usually detectable after a longer period of time, as the incubation period lasts between 2 and 6 weeks. The general recommendation is to undergo the test 3 months after possible exposure, due to the window period. This window describes the time between the time of probable HIV infection and the expiration of 3 months when HIV positivity cannot be definitively proven or ruled out.^[5] 

There are 3 types of HIV tests:

• Antibody test. Antibodies are proteins our immune system produces in response to a foreign substance in our body, such as a virus. This test can detect the presence of antibodies to HIV. Most rapid tests and self-tests for HIV use antibodies for detection. Typically, this method can detect the virus in 23 to 90 days postexposure. 
• Antigen/antibody test. Antigens are foreign substances, in this case, parts of the virus, that activate a person’s immune system, also leading to the production of antibodies. This test looks for both antigens and antibodies to HIV in your blood. Typically, HIV antigens, like p24, appear in the bloodstream before antibodies. Using this method, HIV can be detected 18 to 45 days after exposure. 
• Nucleic acid test (NAT). This test looks for the virus itself. It can detect HIV 10 to 33 days postexposure. 

Typically, the initial test to detect HIV is either an antibody or antigen/antibody test. NAT is not routinely used for screening, however it can provide information about viral load, or how much virus is in your blood.

There are two possible states of your blood test result: positive or negative

• Your HIV test results are positive, indicating the presence of the virus. It's important to remain calm. Contact your healthcare provider immediately for follow-up tests and discussion about treatment options. It is important to remember that HIV is a manageable condition. If your results are positive, contact your current and former sexual partners immediately to prevent further spread of the disease.
• Your HIV test results are negative, meaning the virus has not been detected in your blood. To maintain this, it is recommended to engage in safe behaviors such as using protection during sexual activities and getting tested regularly.

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Treatment Options

Thanks to decades of thorough research, several treatment options are available now. The primary treatment for HIV is a class of medication known as antiretroviral therapy (ART). The drugs are typically given in combination, to maximize efficiency. ART doesn't cure HIV, but it can control the virus effectively so that it becomes undetectable in blood tests and cannot be passed on to others.^[6-8] 

• Nucleoside/nucleotide reverse transcriptase inhibitors (NRTIs) and non-nucleoside reverse transcriptase inhibitors (NNRTIs) block a key virus enzyme known as reverse transcriptase.
• Protease inhibitors (PIs) block the protease enzyme, preventing the virus from dividing into individual viruses that can infect other cells.
• Integrase inhibitors prevent the virus's genetic material from integrating into the DNA of the host cell.
• Entry or fusion inhibitors block the virus from entering the host cell.

Alongside ART, people living with HIV may require other treatments to manage symptoms, prevent or treat opportunistic infections, and manage other health conditions.

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The Science Behind

Below you can dive into more detailed information about HIV. Find out how genetics can influence the development of the disease and the underlying molecular mechanisms.

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Molecular Mechanisms

HIV is a retrovirus. A key feature of retroviruses is that they carry their genetic material as RNA rather than DNA. When HIV enters a human cell, it uses an enzyme called reverse transcriptase to convert its RNA into DNA. This is opposite to the usual flow of information in cells, which is from DNA to RNA, and that's why these viruses are called retroviruses.

This newly formed DNA, containing the genetic instructions of HIV, is then integrated into the host cell's genome, a process mediated by another viral enzyme, integrase. With this integration, the HIV genetic material essentially becomes part of the host cell's DNA. Consequently, the normal cellular machinery transcribes and translates the integrated viral DNA, producing new virus particles.

The final step of the viral cycle involves the viral enzyme protease. It cleaves long protein chains into specific pieces necessary to assemble mature and infectious virus particles. 

The in-depth understanding of this complex cycle has enabled the development of antiretroviral drugs, such as reverse transcriptase inhibitors, integrase inhibitors, and protease inhibitors. Each of these drugs targets a specific stage in the HIV cycle.^[9,10]

If you are interested in a more detailed explanation of the HIV life cycle, there are many useful resources on the internet. For example: How the HIV Infection Cycle Works - Animated microbiology 

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Genetics and HIV

Genetics can influence a person's susceptibility to HIV infection and progression of the disease once infected, but it's important to note that most of the risk for HIV acquisition comes from behaviors, such as unprotected sex or sharing needles while taking drugs, rather than from genetic factors.

For example, individuals carrying two copies of a specific mutation in the CCR5 gene, known as CCR5-delta32 (homozygous), significantly reduced their susceptibility to the most common type of HIV, HIV-1. The CCR5 protein acts as a receptor on the surface of immune cells, allowing HIV to enter and infect the cell. The CCR5-delta32 mutation prevents the normal CCR5 protein from being expressed on the surface of cells, effectively blocking the primary entry point of the virus.^[11,12]

Another example involves the gene HLA-B, which helps the immune system recognize and destroy infected cells. Some variants of HLA-B appear to slow the progression of HIV to AIDS, while others may speed it up.^[13,14]

However, it is crucial to keep in mind that only safe and conscious behavior and choices can protect you from this disease. 

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Recommendations

The recommendations regarding HIV typically encompass prevention and frequent testing. In case of contagion, it includes treatment and living with the infection^[1-4,9]:

• The primary advice for HIV prevention is to practice safe sexual behavior. This includes using condoms and considering pre-exposure prophylaxis (PrEP) if you are at high risk. 
• Using clean needles and equipment can significantly reduce the risk for those who use injections. 
• Regular testing for HIV and other sexually transmitted infections is also essential to HIV prevention.
• If someone tests positive for HIV, they should start antiretroviral therapy (ART) and notify their current and former sexual partners as soon as possible.
• It's recommended that individuals living with HIV maintain regular medical check-ups, continue taking their medications as prescribed, and make healthy lifestyle choices to boost their immune system. Mental health support may also be beneficial. 
• Women living with HIV who are pregnant, planning to become pregnant, or breastfeeding should take ART for their health and to reduce the risk of transmitting HIV to their baby.

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There is a social stigma surrounding HIV that can cause people to delay or refuse to get tested. However, it is important to overcome these uncomfortable feelings because testing can lead to an early diagnosis, thus preventing the spread of the disease. 

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The information and tests provided on our website are for educational purposes only and are not a substitute for professional medical advice. Always consult with your healthcare provider before making health decisions. Our tests do not diagnose or treat diseases. Individual results may vary and should be discussed with a healthcare provider.