A detailed understanding of the dynamics of the early stages of Zika virus (ZIKV) infection is needed to inform diagnostic testing algorithms and prevention interventions, as existing evidence is based on case reports and cross-sectional observations, primarily from returning travelers. To estimate the presence and duration of detection of ZIKV RNA in body fluids and anti-ZIKV IgM antibody in individuals with acute ZIKV infection, we established the Zika virus
Persons in whom ZIKV was detected by RT-PCR in urine or blood in a Puerto Rico enhanced arboviral clinical surveillance site were enrolled. Serum, saliva, urine, and semen/vaginal secretions were collected weekly for the first month and at 2, 4, and 6 months. All specimens were tested by RT-PCR and serum was tested by anti-ZIKV IgM ELISA. Among those with ZIKV RNA in any specimen at week 4, biweekly collection continued until all specimens tested negative. Time to loss of ZIKV RNA detection in each body fluid was estimated using parametric Weibull regression models. We estimated the 50th and 95th quantiles with their 95% confidence intervals (95% CI).
Among 150 participants, 88% (132/150) of participants had detectable ZIKV RNA in ≥1 serum specimen, 62% (92/149) in urine, 10% (15/147) in saliva, 1/50 (2%) in vaginal secretions and 56% (31/55) in semen. The 50th and 95th percentile for days post-illness-onset until loss of ZIKV RNA detection were respectively, 14 (95% CI: 11-17) and 54 (95% CI: 43-64) in serum, 8 (95% CI: 6-10) and 39 (95% CI: 31-47) in urine, and 34 (95% CI: 28-41) and 81 (95% CI: 64-98) in semen. Few had detectable RNA in saliva and vaginal secretions.
Our interim analyses provides crucial information about time to clearance of ZIKV RNA in persons with acute ZIKV infection and detectable ZIKV RNA at enrollment. Prolonged time to ZIKV RNA clearance in serum may have implications for diagnosis and prevention. Current sexual prevention guidelines recommend that men use condoms/abstain from sex for 6 months after ZIKV exposure; in this study 95% of men cleared ZIKV RNA from semen over this time period.