Human immunodeficiency virus (HIV) is the cause of HIV infection. HIV infects a specific type of immune system cells called CD4 lymphocytes or helper T cells. The role of healthy CD4 cells is to organize other immune cells to respond to infection, effectively stimulating the immune response. When HIV infects a CD4 cell, it hijacks the process by which the cell replicates itself and uses it to produce copies of HIV instead, releasing them into the body to infect more CD4 cells.
HIV also destroys CD4 cells, making it difficult for the body to coordinate an immune response to invading pathogens such as viruses or bacteria. Lowered levels of CD4 cells weaken the immune system and leave the body unable to protect itself from cancer and infections.
DNA and RNA are different types of molecules used to communicate genetic instructions. Most viruses translate DNA into RNA, which instructs the cell on which proteins to produce. HIV is known as a retrovirus due to its ability to reverse the usual process, translating its RNA into DNA and inserting it into the nucleus of the cell, which then reproduces more HIV.
In people infected with HIV, the virus is carried in blood, semen, preseminal fluid, vaginal secretions, rectal fluid, and breast milk. To spread HIV, the infected fluid must come into contact with an uninfected person in one of three specific ways:
HIV is most commonly passed to another person during unprotected (without condoms) anal or vaginal sex or by sharing used needles, syringes, or other injection equipment. HIV can also be spread by improperly sanitized medical, dental, or tattoo instruments. HIV is rarely spread via blood transfusions, transplants, or medical instruments in countries with strict biosafety laws.
HIV can also be passed to a fetus during pregnancy or to a baby while giving birth or breastfeeding. It is extremely rare but technically possible to contract HIV from oral sex.
Using a new synthetic (latex or polyurethane) condom every time you have vaginal or anal sex is extremely effective for preventing HIV transmission. To protect you, the condom must be put on correctly before penetration begins.
The U.S. Food and Drug Administration (FDA) has approved various medications for HIV prevention. Known as preexposure prophylaxis (PrEP), these medications stop HIV from replicating in your body. They are available as pills or as long-acting injections.
PrEP pills contain the drugs tenofovir and emtricitabine, and they are sold under the brand names Truvada and Descovy. These formulations each have a different type of tenofovir, and your doctor will help you figure out which is best for you. You need to take these medications consistently every day for them to be effective.
Cabotegravir (Apretude) is a long-acting PrEP injection that’s given once every two months. Like PrEP pills, you’ll need to take the injections consistently and on time. Researchers have found that Apretude reduces transmission risk by 90 percent compared to Truvada in studies that show the most efficacy, according to the FDA.
Lenacapavir (Yetzugo) is the newest PrEP option approved by the FDA. It is a long-acting injectable given only twice a year (every six months), offering a convenient alternative for people who prefer not to take daily pills or more frequent injections. Lenacapavir works by targeting a different part of the virus than other PrEP medications — a capsid protein — to prevent HIV from replicating.
Like other PrEP options, lenacapavir requires a negative HIV test before each dose. Because it stays in the body for up to a year, it’s especially important to keep up with scheduled injections to avoid developing drug-resistant HIV.
When a person who is HIV-negative takes oral PrEP pills properly, their risk of contracting HIV from an infected sexual partner is reduced by about 99 percent, according to the Centers for Disease Control and Prevention (CDC). PrEP pills reduce the risk of contracting HIV from sharing needles with an infected person by at least 74 percent, according to the agency.
After being on treatment for several months, many people living with HIV can bring their viral load (the amount of HIV in their blood) down to such low levels that it is undetectable. People with an undetectable viral load are believed to be incapable of spreading HIV to others through sexual means as long as they continue to consistently take treatment. Effective treatment for HIV is now seen as prevention from getting HIV.
If you’re interested in learning more about taking PrEP to lower your risk of HIV, talk to your healthcare provider.
If you think you may have been exposed to HIV, you can take postexposure prophylaxis (PEP) to prevent HIV infection from taking hold. PEP contains a few specific medications that are normally used to treat HIV. PEP is most effective when taken within 72 hours (or three days) of exposure to the virus. You’ll need to take your PEP medications every day for four weeks (28 days), and you should follow up with your doctor.
Unfortunately, PEP isn’t 100 percent effective. The sooner you start taking PEP medications, the more time it has to start working.
You’ll have better chances of preventing HIV if you take your PrEP medications as prescribed, in addition to using other prevention measures. In recent late-stage clinical trials, nearly 100 percent of participants remained HIV-negative on Yetztugo.
It’s important to talk to your primary care provider or an emergency room doctor as soon as you think you’ve been exposed to HIV. They can determine whether you need PEP and which medications to prescribe.
Decades ago, when little was known about HIV and AIDS, people were not sure how the virus was transmitted. Myths surrounding HIV persist, and some people still fear close contact with those who are living with HIV. However, clinical studies have proved that HIV cannot survive outside the body — including on skin, in water, or in the air — and many bodily fluids do not carry HIV.
The following types of contact cannot transmit HIV between people:
Additionally, HIV can’t be transmitted by coming into contact with another person’s:
Anyone — regardless of age, sex, sexual orientation, or ethnic background — can become infected with HIV.
Lifestyle choices and other behavioral factors have the most influence over who gets HIV.
High-risk behaviors include:
During sex, the person receiving penetration (the “bottom”) has the highest risk of contracting HIV. The person performing penetration (the “top”) has the highest risk of transmitting HIV.
The risk of contracting HIV increases if you have other sexually transmitted infections (STIs) such as herpes. This is because the same behaviors that raise your risk of an STI can also contribute to your risk of HIV infection. Additionally, HIV can enter the body through a skin break or open sore caused by an STI.
Someone with an uncircumcised penis is more likely to contract HIV than someone who is circumcised, according to the CDC. Studies have shown that circumcised males are 60 percent less likely to contract HIV during sex with a female than those who are uncircumcised, per the CDC.
Sexual orientation, sex, ethnicity, and geographic area all influence the risk of contracting HIV.
Men who have sex with men have the highest rate of HIV infection, nearly 70 percent of those diagnosed in the U.S. in 2022, according to HIV.gov.
Ethnic background has a strong influence over HIV risk. Black/African American people accounted for 37 percent of new HIV diagnoses in the U.S. in 2022, according to HIV.gov, although they make up only 12 percent of the population. Hispanic/Latino people also have a higher risk of contracting HIV, according to HIV.gov. In 2022, around 33 percent of new HIV diagnoses were in Hispanic/Latino people, although they were 18 percent of the U.S. population.
In general, males are more likely to contract HIV than females, according to HIV.gov. Data for 2022 shows that 81 percent of new HIV infections occurred in males. Additionally, transgender people accounted for 2 percent of new infections in the U.S. in 2022, according to the CDC. Of these individuals, many were Black/African American (41 percent) and Hispanic/Latino (39 percent).
People in their 20s and 30s are more likely to be diagnosed with HIV than those in other age groups. In 2022, 37 percent of new HIV infections in the U.S. occurred in people between the ages of 25 and 34, per HIV.gov.
The risk of HIV infection also varies by geographic region in the U.S. In 2022, nearly half of new HIV infections were in the Southern states, per HIV.gov.
It’s important to use the different methods described here to prevent the spread of HIV. Talk to your doctor about PrEP options available to you.
If you think you may have been exposed to HIV, seek emergency care and get tested right away. Be sure to discuss any positive test results or other questions you may have with your doctor. We can all take steps to help curb the spread of HIV and reduce the overall number of infections.
On myHIVteam, the social network for people with HIV and their loved ones, members come together to ask questions, give advice, and share their stories with others who understand life with HIV.
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A myHIVteam Member
Me and my husband are both positive we don't use condoms we had to the first few weeks after testing positive but that was almost 4 years ago when I was first diagnosed i was scared my grandbabies… read more