Zika: viral shedding limited to 30 days in men

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Takeaway

  • Although Zika virus (ZIKV) may persist for >6 months in semen of men with symptomatic infection, viral shedding appears to be short-lived (<30 days post-illness onset; PIO), limited to RNA viral loads >7.0 log10 copies/mL.
  • Molecular detection alone may be insufficient for determining ZIKV transmission risk.

Why this matters

  • Men with symptomatic ZIKV may only risk sexual transmission during 30-day PIO, although intermittent viral shedding remains possible.
  • Adherence to ZIKV prevention guidelines is recommended.

Key results

  • 1327 samples, 184 men.
  • Median time illness onset to the first sample collection was 42 days (range, 14-222 days); longest: 304 days.
  • 61% (22/36) of men who submitted samples <30 days PIO had detectable ZIKV RNA in semen, declining to <7% (9/132) in samples collected 91-120 days, and 1% (1/91) in 1 sample collected 281 days PIO.
  • 3/78 samples had detectable ZIKV RNA >30 days PIO (limited to >7.0 log10 copies/mL).
  • 13% (8/60) had intermittent shedding.
  • Longer time to RNA clearance associated with: increasing age (P=.01), absence of joint pain (P=.003), less frequent ejaculation (P=.002).

Study design

  • Prospective study analyzing frequency, duration, pattern of, and risk factors for prolonged ZIKV shedding in semen.
  • Funding: CDC.

Limitations

  • Findings limited to symptomatic men.
  • Confounders unexplored.
  • Potential contamination of some samples.