[Zika virus and sexual transmission; when and for how long does one need to use a condom?]

- More evidence has become available concerning the sexual transmission of Zika virus and viral shedding in semen, which has led to the expansion of international guidelines for prevention of sexual transmission; Dutch guidelines have not been altered.- Internationally, the use of condoms during sex or sexual abstinence is advised for the duration of the pregnancy. Furthermore, when actively trying to conceive one should use a condom for six months.- In the Dutch guidelines, men who have visited a Zika virus epidemic area are advised to use a condom for 2 months upon return, irrespective of their partner possibly being pregnant or their wish to conceive.- Based on reports to the World Health Organisation and patient reports, the serial interval between disease onsets of both sexual partners is 4-44 days (median: 15).- Zika virus RNA is often no longer detectable in semen 2-3 months after disease onset.- International guidelines are based on the maximum detection period of Zika virus RNA and on virus isolation. Dutch prevention guidelines, on the other hand, are based on the longest serial interval known for sexual transmission (44 days).- Detection of Zika virus RNA in semen does not give a definitive answer on contagiousness. Currently, following the Dutch prevention advice is the best option in order to prevent sexual transmission.