Low HIV Blood Levels Reduce Risk and Enhance Treatment

By Healthy Living News

Two new studies verify that blood levels of HIV are important in determining risk of HIV sexual transmission and the success of HIV therapy.

The first study revealed that the risk of HIV transmission is greatly diminished when HIV blood levels, also known as viral load, are at low levels. That study also confirmed a recent break-though advance in HIV prevention.

Published in the Journal of Infectious Diseases, the study included 3,297 HIV-discordant heterosexual African couples (where one person is HIV-infected and the other is not). Viral load levels were frequently measured in the infected partner along with HIV genetic testing to link any transmitted virus by the HIV-infected partner to the uninfected one.

The study reveals that in the infected partner, the lower the viral load, the lower the risk of sexually transmitting the virus to the uninfected partner. Each low level decrease was associated with a three fold decrease in transmission risk.

The study also indirectly confirms the results of the breakthrough "Treatment as Preventions" study released last year. That study, known as HPTN 052, proved that lowering viral load through early initiation of HIV therapy reduces transmission of the virus to uninfected partners by up to 96 percent.

But can Treatment as Prevention be improved further through treatment and technology?

Another study reveals that treatments that suppress HIV to very, very low levels may guarantee the long-term success in treating the virus and preventing its transmission to others.

The study, published in Clinical Infectious Disease, examined how well newer viral load tests predict HIV treatment failure. Tests used by many clinics still measure viral load down to 50 HIV copies per a milliliter sample of blood. But newer tests detect viral load down to even lower levels. So the question was asked, what are the levels of treatment success and failure among those measured with these newer tests?

The study tested 1247 patients using the old ultrasensitive and the newer ultra-ultrasensitive viral load tests. For those who tested below 50 copies, or undetectable on the old test, 211 eventually experienced a rebound in viral load to detectable levels above 50. Before they did, a third of them whose virus rebounded (34 percent) measured between 40 and 49 HIV copies on the ultra-ultrasensitive tests. For those with even lower viral loads between 39 and about 10 copies, 11 percent eventually broke through to above 50. For those down to under 10 HIV copies, or undetectable levels on the ultra-ultrasensitive test, only 4 percent eventually rebounded above 50.

Putting it another way, those with an ultra-ultrasensitive viral load between 39 and 10 HIV copies were twice as likely to rebound to above 50 than those testing undetectable on the new test. Those who tested between 40 and 49 were more than a four-times as likely to rebound.

Other studies show that for those on treatment, viral load levels consistently higher than 50 lead to HIV drug resistance. Forty of those in the study whose viral load broke through eventually had viral load increases above 400. Those in the study with ultra-ultrasensitive levels between 40-49 also tended to be less compliant in taking their medications.

Those who had been on HIV therapy longer, however, tended to suppress HIV to the very lowest levels on the new tests.

It should be noted that being HIV undetectable on any viral load test does not mean being cured of HIV. Studies show there is no guaranteed "safe" level of HIV viral load, only levels that show a reduced risk of transmitting the virus. HIV is still, in theory, transmissible even if your viral load is undetectable. Very low amounts of HIV may still be in the blood and larger amounts are still in the lymph nodes, spleen, or brain and possibly even semen. Viral load levels can also spike from an infection or after a vaccination.