Home Search Abstracts Browse Sessions Program Committee E-mail Abstract Author View Session

Session 60 Poster Abstracts
Primary Infection: Viral Pathogenesis
Tuesday, 1:30 - 3:30 pm
Poster Hall


389
Intermittent Low-Level Viremia During the Eclipse Phase of Primary HIV-1 Infection.
E W Fiebig*1,2, C Heldebrant3, R Smith3, A Conrad3, E L Delwart1,4, and M P Busch1,4,5
1Univ. of California, San Francisco, USA; 2San Francisco Gen. Hosp., CA, USA; 3Natl. Genetics Inst., Los Angeles, CA, USA; 4Blood Ctrs. of the Pacific, San Francisco, CA, USA; and 5Blood Systems Inc., Scottsdale, AZ, USA

Background: To determine if HIV is present during the eclipse phase of primary HIV infection, i.e., the period between exposure and the onset of quantifiable, sustained viremia.

Methods: Anonymized panels consisting of plasma samples collected on average twice weekly from source plasma donors newly infected with HIV were obtained from a commercial source. Panel samples were analyzed for the several week time period prior to HIV detection by a screening RNA assay. Quantitative HIV-1 results were available for each sample. A total of 31 plasma panels were reviewed for the presence of at least two samples with <100 genome copies/mL HIV-1 RNA, followed by several specimens with 100 copies/mL HIV-1 RNA or greater. Fifteen panels with a total of  74 samples were included; 5 to 10 replicates of samples with <100 copies/mL HIV-1 RNA were retested with a sensitive qualitative RT- PCR assay (95% detection at 5 cp/mL).

Results: Of the 74 samples, 25, representing 13 of the 15 panels, had <100 copies/mL HIV. In 7 of 13 panels only 1 such sample each was identified immediately preceding a sample with >100 copies/mL. The remaining 6 panels (46%) each had 3 to 6 such samples. The percentage of positive replicates per sample ranged from 10 to 100%; the concentration of HIV in these plasma samples is estimated to be between 1 to 10 copies/mL, based upon the statistics of viral detection by the highly sensitive qualitative assay. The earliest positive sample preceded the first sample with >100 copies/mL HIV by 25 days; the median was 20 days.

Conclusions: Low-level intermittent viremia is not uncommon during the eclipse phase of primary HIV infection. It is not known if blood from recently exposed persons is infectious during this period. But because of the low viral concentrations observed during viremic blips and their transient nature, at least the risk of secondary transmissions by the sexual route can be expected to be minimal in this very early stage of  viral dissemination.

Keywords: primary HIV infection; viremia; eclipse phase