Study Indicates Zika Virus Persists Longest in Semen
In the vast majority of men, Zika RNA takes approximately 4 months to clear from semen, according to the Centers for Disease Control and Prevention’s (CDC) ZIKV Persistence (ZiPer) cohort study final report, which estimated the frequency and duration of detectable Zika virus in RNA in human body fluids, including serum, urine, saliva, semen, and vaginal secretions. The study evaluated bodily fluid samples from 295 recently infected people in Puerto Rico, including 94 men who provided semen samples. Bodily fluids were collected from all participants weekly for the first month and at 2, 4, and 6 months.
Medians and 95th percentiles for the time until the loss of ZIKV RNA detection were as follows:
- Serum: 15 days (95% confidence interval [CI], 14 to 17) and 41 days (95% CI, 37 to 44), respectively
- Urine: 11 days (95% CI, 9 to 12) and 34 days (95% CI, 30 to 38) , respectively
- Semen: 42 days (95% CI, 35 to 50) and 120 days (95% CI, 100 to 139), respectively
- Saliva <5% of participants had detectable ZIKV RNA
- Vaginal secretions: <5% of participants had detectable ZIKV RNA.
These data support the CDC’s new modified sexual activity recommendations regarding Zika virus exposure:
- Men with possible exposure should use condoms or abstain from sex for ≥3 months after exposure, even if asymptomatic
- Women with possible exposure should wait ≥2 months from the beginning of Zika symptoms or most recent exposure before trying to become pregnant.
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Paz-Bailey G, Rosenberg ES, Doyle K, et al. Persistence of Zika Virus in Body Fluids – Final Report. N Engl J Med. 2017;379(13):1234-1243. doi: 10.1056/NEJMoa1613108.
Centers for Disease Control and Prevention. Zika virus: sexual transmission & prevention. Updated October 12, 2018. Accessed October 15, 2018.