Undetectable viremia without antiretroviral therapy in patients with HIV seroconversion: an uncommon phenomenon?

The objective of this study was to identify the frequency and characteristics of patients with human immunodeficiency virus (HIV) infection who had spontaneously achieved viremia below the detection limit of either 400 or 500 copies/mL (depending on the test used) and to describe the duration of undetectable viremia without antiretroviral therapy (ART).

In the French Agence Nationale de Recherches sur le SIDA SEROCO cohort, 426 patients with HIV seroconversion (i.e., seroconverters) enrolled between 1988 and 1995 had serial measurement of HIV RNA levels during follow-up (with a cutoff date of 31 December 2002). Factors that distinguished those patients who had spontaneously achieved undetectable viremia (> or =2 consecutive viral loads <400 or <500 copies/mL while not receiving ART) were identified by logistic regression. A Cox model was used to estimate the predictive value of factors related to the duration of undetectable viremia.

Undetectable viremia had been spontaneously achieved in 36 of 426 seroconverters. Women (adjusted odds ratio [aOR], 2.44; 95% confidence interval [CI], 1.03-5.80) and subjects with baseline HIV RNA level < or =3.76 log10 copies/mL (aOR, 0.31; 95% CI, 0.11-0.82), baseline HIV DNA level < or =2.61 log10 copies/mL (aOR, 0.14; 95% CI, 0.04-0.44), and high baseline CD4+ cell count (aOR, 1.18 for each 100 cells/mm3; 95% CI, 1.03-1.35]) were more likely to have achieved undetectable viremia. The sustainability of this phenomenon (median duration, 11.9 months; range, 4.6-62.8 months) was associated with low baseline HIV DNA and RNA levels.

Achieving undetectable viremia without ART was not rare, because 6.7% of seroconverters still had a viral load of <400 or <500 copies/mL 5 years after seroconversion. These data should be considered when assessing virologic outcome for patients who interrupt highly active ART initiated during primary infection.