HIV 101: Understanding HIV
By Michelle Betton and Chelsea Bailey | August 26, 2013
The Human Immunodeficiency Virus (HIV) is one of the world’s most confusing and complex viruses. In this series, we will strip away the scientific jargon and provide a straightforward guide to HIV with the Elizabeth Glaser Pediatric AIDS Foundation (EGPAF)’s Director of Basic and Clinical Research Jeffrey Safrit. We break down questions about the virus itself and how it infects and interacts with the human body.
In this first installment, we will discuss some of the basics of HIV and AIDS and how they affect the body. Read more to find out!
What is HIV?
HIV is the virus that causes Acquired Immune Deficiency Syndrome (AIDS). Viruses infect living organisms, like human cells, and use those organisms to multiply. Because antibiotics cannot kill a virus, doctors let common viruses, such as a cold, run their course, allowing the immune system attack and eventually destroy the illness.
But HIV is more complicated. It is a retrovirus, a type of infection that replicates by inserting its genetic blueprint into a host cell, essentially corrupting the cell’s healthy chromosomes forever. HIV targets the immune system and turns the body’s internal shield against itself, hijacking the CD4 white blood cells that naturally defend against illness, and rewiring them to make new copies of HIV. Eventually, the virus destroys the infected white blood cells, which weakens the immune system. Without proper treatment, HIV infection will progress into the disease AIDS.
How does HIV Spread?
HIV is spread through exposure to infected body fluids and can be transmitted multiple ways including blood transfusions, childbirth, and having unprotected sex with someone who is HIV-positive.
Though the disease is contagious, an HIV-positive person is most likely to pass on the virus during the first weeks following infection and later in the course of the disease. During these periods, the body rapidly produces new copies of the virus, which results in an exponentially higher “viral load,” and an increased probability of transmitting the virus.
People who are infected with HIV do not get sick immediately. It can take the body months to attempt to fight off the virus and for a patient to test HIV-positive. So, paradoxically, the period when an HIV-positive person is most infectious coincides with the period he or she is least likely to know their status.
How do children become infected with HIV?
More than 90 percent of HIV infections in children result from mother-to-child transmission. The virus can be passed from a mother living with HIV to her baby during pregnancy, childbirth, or breastfeeding. The risk of transmitting HIV to an infant directly increases in relation to the severity of the mother’s HIV infection -- this is why early prevention and treatment for pregnant women is imperative.
How do we test for HIV?
In resource-limited settings, the most commonly used HIV tests look for HIV antibodies and not for the virus itself. The immune system produces antibodies when it detects a foreign presence, like a virus. Antibody tests, like the HIV rapid test, screen for the presence of HIV antibodies in the blood and can provide results in as little as 20 minutes.
But screening for HIV antibodies isn’t always enough. It can take four to six weeks for the body to produce enough antibodies to trigger a positive test. The period of time between when a person is infected with HIV and when the antibody screening tests positive is called the “window period,” because during this “window,” it’s possible to test negative for HIV, but still have the virus.
To combat this phenomenon, a positive antibody test is typically verified by one that looks for the presence of the virus itself. However, this method is complicated and more costly to run on each patient, especially in resource-limited settings.
How do we treat HIV?
An HIV-positive patient will be enrolled into antiretroviral therapy (ART) when his or her CD4 (white blood cell) count falls below a healthy threshold.
Several different combinations of drugs are used in ART to treat HIV-positive patients. Each medication works by blocking different parts of the lifecycle of the virus. This makes it harder for the virus to multiply which in turn reduces the amount of HIV present in the body. ART represses the virus, allowing the immune system to become stronger. Eventually the patient becomes healthier because the body is again able to resist common infections. While ART can improve quality and length of life, it does not completely destroy the virus or cure the disease.
How do we prevent HIV transmission?
The best way to prevent HIV transmission to an uninfected person is for HIV-positive people to know and disclose their status. Though a positive HIV diagnosis is inevitably life-changing, HIV does not have to be a life-ending illness. Early diagnosis and adherence to treatment of can extend life expectancy for decades, but that’s only if the HIV-infected individual is treated with ART. Medical advances have made it possible for HIV-positive individuals to lead full and healthy lives, but that begins with them knowing their status.
EGPAF’s Chelsea Bailey, Michelle Betton, and Jeffrey Safrit contributed to this blog.