Persistence of Zika Virus in Body Fluids - Final Report

Abstract

Background: To estimate the frequency and duration of detectable Zika virus (ZIKV) RNA in human body fluids, we prospectively assessed a cohort of newly infected participants in Puerto Rico.

Methods: We evaluated samples obtained from 150 participants (including 55 men) in whom ZIKV RNA was detected on reverse-transcriptase-polymerase-chain-reaction (RT-PCR) assay in urine or blood in an enhanced arboviral clinical surveillance site. We collected serum, urine, saliva, semen, and vaginal secretions weekly for the first month and then at 2, 4, and 6 months. All specimens were tested by means of RT-PCR, and serum was tested with the use of anti-ZIKV IgM enzyme-linked immunosorbent assay. Among the participants with ZIKV RNA in any specimen at week 4, biweekly collection continued until all specimens tested negative. We used parametric Weibull regression models to estimate the time until the loss of ZIKV RNA detection in each body fluid and reported the findings in medians and 95th percentiles.

Results: The medians and 95th percentiles for the time until the loss of ZIKV RNA detection were 14 days (95% confidence interval [CI], 11 to 17) and 54 days (95% CI, 43 to 64), respectively, in serum; 8 days (95% CI, 6 to 10) and 39 days (95% CI, 31 to 47) in urine; and 34 days (95% CI, 28 to 41) and 81 days (95% CI, 64 to 98) in semen. Few participants had detectable ZIKV RNA in saliva or vaginal secretions.

Conclusions: The prolonged time until ZIKV RNA clearance in serum in this study may have implications for the diagnosis and prevention of ZIKV infection. Current sexual-prevention guidelines recommend that men use condoms or abstain from sex for 6 months after ZIKV exposure; in 95% of the men in this study, ZIKV RNA was cleared from semen after about 3 months. (Funded by the Centers for Disease Control and Prevention.).

Figure 1. Time until the Clearance of Zika Virus RNA in Serum, Urine, and Semen

Shown are models of the time until the loss of Zika virus (ZIKV) RNA detection after the onset of symptoms in serum (Panel A), urine (Panel B), and semen (Panel C) obtained from 150 study participants, as estimated with the use of Weibull regression. To estimate model-derived percentiles for the time until virus clearance at the population level, we assumed that all infected participants had ZIKV RNA in all specimens at symptom onset. Also shown are medians and 95th percentiles of the time until the loss of detection, the key values that were reported in this preliminary study. Blue shading denotes 95% confidence intervals. Data for 4 participants who were asymptomatic at the time of enrollment were excluded from the estimates of the time until the loss of RNA detection, since the number of days after the onset of symptoms could not be determined.