Viral Load

What is viral load?

Viral load is the number of copies of HIV in a given part of the body.  Viral load is usually measured in the blood, but the virus is also present in other tissues and bodily fluids, including semen and rectal secretions. Viral load is highest during the first two months of infection. High viral load increases the likelihood of transmitting HIV to a sexual partner.

Are viral loads always high?

After the first few months of HIV infection, viral load decreases naturally.  Viral load is usually lowered even further to undetectable levels after several weeks of treatment. An undetectable viral load means the number of copies of HIV is so low that medical tests can’t pick them up. Guys with an undetectable viral load have a lower risk of transmitting HIV to sexual partners than when their viral load is detectable. Treatment is the best way to achieve an undetectable viral load.

What affects viral load?

Viral load is influenced by type and length of HIV treatment, following the directions for taking HIV treatment, and the presence of other infections, including STIs.

How is viral load tested?

Blood viral load tests are given to HIV-positive guys on ARV treatment every three months in British Columbia. Guys who are HIV positive but not on treatment should still have their viral load monitored by a doctor.  Currently, viral load tests for semen and rectal secretions aren’t available in British Columbia.

Viral load in blood is not always the same as viral load in semen and rectal secretions.

Most of the time, when viral load is undetectable in blood, it’s also undetectable in semen and rectal secretions. In some cases, guys with an undetectable blood viral load have a viral load in their semen that is high enough to be infectious. However, this is relatively rare, and can be prevented by taking treatment as prescribed and getting tested and treated for STIs.

What does viral load mean for HIV-positive guys?

There are a number of ways to reduce viral load in blood, semen and rectal fluids.

  • Take treatment as prescribed by your doctor. This is the most important factor in keeping your blood viral load undetectable.
  • Get tested for other STIs frequently. STIs in the genital tract (inside the penis) increase viral load and increase the risks to sex partners. Most STIs can be treated easily once they are detected.
  • Talk to your doctor about using protease inhibitor and/or nonnucleoside reverse transcriptase inhibitors; these may do a better job reducing viral load in semen.

What does viral load mean for HIV-negative guys?

  • Condoms are still the best way to prevent HIV, even if partners have undetectable blood viral loads.
  • If your partner is HIV positive, taking treatment as prescribed by his doctor and monitoring his blood viral load and STI status regularly will reduce the chances you will become HIV positive from condomless anal sex.
  • Consider talking to your partner and his doctor to reduce the risk of HIV transmission.