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What Does HIV Viral Load Mean?

What is a viral load?

An HIV viral load is the amount of HIV measured in a volume of blood. The goal of HIV treatment is to lower viral load to be undetectable. That is, the goal is to reduce the amount of HIV in the blood enough so that it can’t be detected in a laboratory test.

If you’re living with HIV, it can be helpful to know your HIV viral load because it tells you how well your HIV medication (antiretroviral therapy) is working. Read on to learn more about HIV viral load and what the numbers mean.

How HIV viral load affects CD4 cell count

HIV attacks CD4 cells (T-cells). These are white blood cells, and they’re part of your immune system. Your CD4 count provides a rough assessment of how healthy your immune system is. People who don’t have HIV usually have a CD4 cell count between 500 and 1,500.

A high viral load can lead to a low CD4 cell count. When CD4 count is below 200, the risk of developing an illness or infection is higher. This is because having a low CD4 cell count makes it harder for the body to fight infection, increasing the risk of illnesses such as severe infections and some cancers.

Untreated HIV can cause other long-term complications and can develop into AIDS. However, when HIV medication is taken daily as prescribed, the CD4 count tends to increase over time. The immune system gets stronger and better able to fight infections.

Measuring viral load and CD4 count shows how well HIV treatment is working both to kill the HIV in the bloodstream and to allow the immune system to recover. The ideal results are to have an undetectable viral load and high CD4 count.

Measuring your viral load

Viral load testing shows how much HIV is in 1 milliliter of blood. A viral load test is done at the time someone is diagnosed with HIV before treatment is started, and again from time to time to confirm that their HIV treatment is working.

To raise your CD4 count and lower your viral load, you have to take your medication regularly and as instructed. But even if you take your medication as prescribed, taking other prescription and over-the-counter (OTC) medications, recreational drugs, and herbal supplements can sometimes interfere with the effectiveness of HIV treatment. Check with your doctor before starting any new medications, including OTC and prescription drugs and supplements.

If your test shows that your viral load hasn’t become undetectable or that it’s gone from being undetectable to detectable, your doctor may adjust your antiretroviral therapy (ART) regimen to make it more effective.

What your viral load means about HIV transmission

The higher the viral load, the higher the probability of passing HIV on to someone else. This could mean passing the virus to a partner through unprotected sex, to someone through sharing needles, or to a baby during pregnancy, delivery, or breastfeeding.

When taken consistently and correctly, ART decreases viral load. This decreased viral load reduces the risk of passing HIV on to someone else. Alternatively, not taking ART consistently or at all increases the risk of passing HIV to someone else.

Having an undetectable viral load doesn’t mean you’re cured, because HIV can still hide in other parts of the immune system. Rather, it means the medication you’re taking is effective at suppressing the growth of the virus. Ongoing suppression can only be achieved by continuing to take your medication.

If you stop taking your medication, you risk your viral load going back up. And if your viral load becomes detectable, you can pass the virus to others through bodily fluids such as semen, vaginal secretions, blood, and breast milk.

Mother-to-child transmission

If you’re pregnant and living with HIV, taking ART during pregnancy and labor dramatically reduces the risk of passing HIV to your baby. Many women living with HIV are able to have healthy, HIV-negative babies by accessing good prenatal care, which includes support for ART.

Babies born to HIV-positive mothers receive HIV medication for four to six weeks after birth and are tested for the virus over the first six months of life.

According to the Centers for Disease Control and Prevention (CDC), you should avoid breastfeeding your baby if you have HIV. However, the World Health Organization (WHO) recommends breastfeeding even for women with HIV.

Sexual transmission

Having an undetectable viral load means that the risk of passing HIV to someone else is close to zero, assuming that the person with HIV and their partner don’t have any sexually transmitted infections (STIs).

Two 2016 studies, in the Journal of the American Medical Association and The New England Journal of Medicine, found no transmission of the virus from an HIV-positive partner who had been on ART for at least six months to a negative partner during unprotected sex.

However, researchers are unsure about the effects of STIs on risk of HIV transmission in treated individuals. If you have an STI, it might increase your risk of transmitting HIV to others even if HIV isn’t detectable in your blood.

Tracking your viral load

It’s important to track your viral load over time. Any time you have an increase, it’s a good idea to find out why. An increase in viral load can occur for many reasons, such as:

  • not taking ART consistently
  • the HIV has mutated (changed genetically)
  • ART isn’t the right dose
  • a lab error occurred
  • having a concurrent illness

If your viral load increases after being undetectable while you’re on treatment with ART, or if it doesn’t become undetectable despite your treatment, your doctor will likely order additional testing to determine the reason.

How often should you test your viral load?

The frequency of viral load testing varies. Typically, viral load testing is done at the time of a new HIV diagnosis and then intermittently over time to confirm that ART is working.

A viral load usually becomes undetectable within three months of starting treatment, but it often happens faster than that. A viral load is often checked every three to six months, but it may be checked more often if there is concern that the viral load may be detectable.

Keeping your partner safe

Whatever your viral load, it’s a good idea to take steps to protect yourself and your sexual partner. These steps may include:

  • Taking your medication. Take your ART regularly and as directed. Taking your medication daily and having an undetectable viral load dramatically decreases your risk of passing HIV to others.
  • Getting tested for STIs. Given the potential effect of STIs on risk of HIV transmission in treated individuals, both you and your partner should be tested and treated for STIs.
  • Practicing safer sex. Using condoms and engaging in sexual activities that don’t involve exchange of bodily fluids lowers your risk of transmission.
  • Considering PrEP. You may want to encourage your partner to talk to their doctor about pre-exposure prophylaxis, or PrEP. This medication is designed to prevent people from getting HIV. When taken as prescribed, it decreases the risk of acquiring HIV through sex by more than 90 percent.
  • Considering PEP. If your partner suspects that they’ve already been exposed to HIV, encourage them to talk to their doctor about post-exposure prophylaxis (PEP). This medication reduces the risk of infection when it’s taken within three days after possible exposure to HIV and continued for four weeks.
  • Getting tested regularly. If your partner is HIV-negative, they should get tested for the virus at least once a year.

Getting support after an HIV diagnosis

An HIV diagnosis can be life-changing, but it’s still possible to be healthy and active. Early diagnosis and treatment can reduce your viral load and risk of illness. Bring any concerns or new symptoms to your doctor’s attention, and take steps to live a healthy life, such as:

  • getting regular checkups
  • taking your medication
  • exercising regularly
  • eating a healthy diet

You can also talk to a trusted friend or relative for emotional support, or ask your doctor about HIV or AIDS support groups. There are many local support groups available for you and your loved ones. You can find hotlines for HIV and AIDS groups by state at

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Written by: Valencia Higueriaon: Nov 22, 2017

This feature is for informational purposes only and should not be used to replace the care and information received from your health care provider. Please consult a health care professional with any health concerns you may have.
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