The estimated cumulative probability of rebound was 70% at 2 months following ART interruption, 80% at 4 months, 94% at 6 months, and 99% at 8 months.
In multivariable analysis, factors significantly associated with longer time to viral rebound included higher baseline CD4 counts (P = .03), higher birth weight (P = .032), and viral suppression within 40 weeks of starting on ART (P = .028)
In contrast, there were no significant associations with other factors in the multivariate model, including sex, baseline viral load, baseline CD8 percentage, HIV stage, status of therapy to prevent mother-to-child transmission, age at ART initiation, length of therapy, or treatment center.
Sensitivity analyses of a few cases in which there was a 4-7 month gap between rebound and the last viral load below 400 copies/mL before rebound showed similar results, Dr. Chan noted.