People taking antiretroviral therapy (ART) for HIV can achieve very low quantities of the virus in their blood, which standard blood tests cannot detect. Doctors describe these individuals as having undetectable HIV or an undetectable viral load.

However, even when a person has undetectable HIV, they will still test positive for HIV. Rather than detecting the virus, HIV antibody tests detect the antibodies the body produces in response.

An undetectable status does not indicate a cure. Although ART prevents the virus from creating copies of itself, the virus remains dormant in the body. However, stopping treatment or missing doses allows the virus to begin multiplying, causing it to become detectable in the blood again.

When a person living with HIV takes their medication daily as prescribed, their viral load drops to undetectable levels within 6 months or even less. A person will be “durably undetectable” if they maintain an undetectable viral load for at least 6 months after first receiving their undetectable status.

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Although there is still no cure for HIV, a person can take medications to manage it. ART is the recommended treatment for all individuals with HIV, regardless of how long they have had the virus and whether they have any medical conditions.

The advice is for people to start with treatment immediately after diagnosis. Delaying treatment allows the infection to damage a person’s immune system, placing them at higher risk of developing AIDS and increasing the likelihood of disease transmission through sexual contact.

Antiretroviral therapy

In a 2016 study, researchers associated early ART with a 93% lower risk of transmitting the infection to a partner compared with delayed treatm

A person needs to take this medication daily, as prescribed. Doing this prevents the HIV infection from progressing and allows the person to live a longer, healthier life. It also minimizes the risk of the virus becoming drug-resistant.

Medication adherence also prevents the sexual transmission of HIV to other people. Research has shown that when ART suppresses a person’s HIV viral load, the risk of transmitting HIV through condomless sex in couples — both heterosexual and men who have sex with men (MSM) — is zero. A 2018 study on MSM couples in Australia, Brazil, and Thailand found similar results.

The various types of approved antiretroviral drugs differ in how they interfere with the life cycle of the virus.

Learn more about ART.

Approved medications

Below is a list of HIV drugs that the Food and Drug Administration (FDA) has approved:

Combination medications are also available, which include two or more of the above drugs in a single pill.

People who have never received ART have different options for initial therapy. However, the standard initial therapy includes two NRTIs with an INSTI. Doctors consider several factors before providing a person with a specific regimen.

Examples of factors that doctors consider include:

  • the person’s preference
  • anticipated adherence
  • pretreatment viral load
  • whether ART is immediate or delayed
  • presence of other infections
  • pregnancy or a desire to get pregnant
  • any underlying health conditions

Learn more about different HIV drugs.

There is no risk of HIV transmitting from a person with an undetectable viral load to an HIV-negative partner. However, people who cannot reach an undetectable status or stay undetectable can take other steps to help reduce this risk.

Abstaining from sex

Refraining from having sex is 100% effective in stopping HIV transmission, pregnancy, and sexually transmitted infections (STIs). However, this may not be a viable option for many people.

Performing safer sexual activities

Instead of performing anal or vaginal sex, couples may choose sexual activities that carry little to no risk of transmission, such as oral sex. Barrier methods, such as condoms, also help prevent the transmission of HIV and other STIs.

Getting tested

Many people may have HIV and not know because there may not be any symptoms in the early stage of the infection. People with STIs are more likely than other people to have HIV. Therefore, getting a test and treatment for STIs is important.

Avoiding breastfeeding

New guidelines from the Centers for Disease Control and Prevention (CDC) state that people with HIV who are breastfeeding or chestfeeding do not need to avoid it if they are on ART and had a sustained undetectable HIV viral load during their pregnancy.

The chance of transmission to the baby is less than 1%.

Taking HIV prevention medicines

Persons who have partners with HIV or use injected recreational drugs can take preexposure prophylaxis (PrEP) to avoid getting HIV. Anyone who suspects that they have had exposure to HIV should take postexposure prophylaxis (PEP) within 72 hours.

HIV medications may sometimes cause side effects. These are mostly manageable, but some may be serious. The side effects vary among drugs. However, a person should not start a new treatment or skip, stop, or cut down on their current medications unless a doctor advises doing so.

When starting ART, it is advisable to ask a doctor about the usual side effects and what to do if they occur.

A person already taking ART should speak with a doctor if they experience any of the following:

The following section answers some common questions on undetectable HIV.

What are the odds of getting HIV from someone who is undetectable?

The National Institutes of Health has confirmed that HIV cannot transmit from people whose HIV is undetectable to others.

How long can HIV stay undetected?

Research from 2021 suggests that HIV could remain undetected indefinitely as long as the person takes their medication regularly. However, some risk factors may predispose a person to returning to a detected status. This includes:

  • being female
  • substance use
  • place of birth outside of the United States
  • lower education level
  • unemployment
  • previous change from undetected to detected

Standard tests that look for HIV in the blood may not pick up undetectable HIV. However, HIV antibody tests may still detect the antibodies the body makes in response to the viral infection.

Taking ART can suppress the virus in a person’s body and lower their viral load. Although a person with undetectable HIV still has HIV, there is no risk of it transmitting to an HIV-negative partner through sex.

A person must take ART medication as prescribed to maintain an undetectable viral load. Otherwise, the virus can multiply in the blood and reach detectable levels.