People who start antiretroviral therapy soon after acquiring HIV are more likely to experience full immune recovery, according to a recent study. Prior research has shown that starting antiretrovirals during acute HIV infection (the first month) can limit the size of the viral reservoir; starting treatment during primary HIV infection (the first six months), before extensive immune damage occurs, is also beneficial.

The HEATHER study included 204 people in the United Kingdom with documented primary HIV infection who started antiretroviral treatment within three months after diagnosis. Even at this early stage, most already showed evidence of immune dysfunction.

Almost everyone achieved a viral load below 200 after starting treatment. However, after nearly three years of follow-up, just 47% reached a CD4 T-cell count above 900 (normal for HIV-negative people is 500 to 1,500), and 64% achieved a normal CD4/CD8 ratio (greater than 1.0). Having a lower CD4 count, CD8 count or CD4/CD8 ratio at treatment initiation was associated with a longer time to CD4 cell recovery. For every day treatment was delayed, there was a lower likelihood of achieving a normal CD4 count and CD4/CD8 ratio.

While there was once uncertainty about when to start antiretrovirals, it is now well established that sooner is better. “Our findings further the rationale for same-day or earlier antiretroviral therapy, even during primary HIV infection, to support more rapid immune recovery,” John Patrick Thornhill, MD, PhD, of Imperial College London, and colleagues wrote.