Six months ago sexual transmission of Zika was considered a rarity, and viewed as unlikely to constitute much of a public health risk. But as time has gone on, evidence has accrued that sexual transmission is much more common than previously believed.
On Friday, Lisa Schnirring of CIDRAP News wrote Zika data point to sexual transmission in women on research that found women in the sexually active age-group (15-65) far more likely to be infected than men.
We've also seen studies on the persistence of Zika Virus (and Zika RNA) in semen, urine, and even saliva (see Fiocruz: Revisting Zika Virus Detection In Saliva & Urine), which have raised (as yet, unanswered) questions over the full range of sexual transmission of the virus.
Today the WHO has released new, interim guidance, which doubles the length of time (from 4 week to 8 weeks) they recommend couples follow safe sex practices or abstain from sex after returning from Zika endemic regions.
They also recommend if the male partner was symptomatic, the waiting period should be extended to six months.
While there isn't sufficient evidence to support non-intercourse sexual transmission of the virus, they do acknowledge the findings of the Zika virus in both saliva and urine, writing:
3. Presence of Zika virus in other body fluids
Publications on the presence of Zika virus in other body
fluids that may be involved in sexual transmission have also been considered. Studies have reported the presence of Zika virus by RT-PCR in saliva 17, 18 and urine 14, 15, 18-25 .
The persistent shedding of Zika virus ribonucleic acid
(RNA) in both fluids has been found up to 29 days after
the onset of infection. Culture of Zika virus in urine 14, 18, 20,26 and saliva 18 has also been reported, with the virus cultured at day six after symptom onset for both fluids.
Follow the link below to download the full 4-page PDF guidance document.
OverviewThe primary transmission route of Zika virus is via the Aedes mosquito. However, mounting evidence has shown that sexual transmission of Zika virus is possible and more common than previously assumed. This is of concern due to an association between Zika virus infection and adverse pregnancy and fetal outcomes, including microcephaly, neurological complications and Guillain-Barré syndrome.
The current evidence base on Zika virus remains limited. This guidance will be reviewed and the recommendations updated as new evidence emerges.