An HIV viral load persistently below the level of detection, or HIV RNA of less than 20 to 75 copies per milliliter, is defined as optimal viral suppression by the National Institutes of Health. HIV RNA, or viral load, is the most important indicator of response to antiretroviral therapy.
Viral load should be measured upon entry to care, the beginning of antiretroviral therapy and then on a regular basis, according to clinical guidelines published by the NIH. CD4 cell counts that provide information on overall immune function are also used to assess response to treatment and monitor HIV infection.
Viral suppression does not mean that a person is cured of HIV infection, according to the NIH. It does help people stay healthy, live longer and reduces the chances of passing HIV on to others.
Of the estimated 1.2 million Americans living with HIV in 2011, only 3 out of 10 had the virus under control. The Centers for Disease Control and Prevention reports that 40 percent were engaged in HIV medical care, 37 percent were prescribed antiretroviral therapy and 30 percent had achieved viral suppression. The CDC advises that all persons diagnosed with HIV should receive medical care and be offered ART as soon as possible after diagnosis, regardless of viral load or CD4 count.