Interim Guidelines for Prevention of Sexual Transmission of Zika Virus — United States, 2016
Zika virus is a mosquito-borne flavivirus primarily transmitted by Aedes aegypti mosquitoes (1,2). Infection with Zika virus is asymptomatic in an estimated 80% of cases (2,3), and when Zika virus does cause illness, symptoms are generally mild and self-limited. Recent evidence suggests a possible association between maternal Zika virus infection and adverse fetal outcomes, such as congenital microcephaly (4,5), as well as a possible association with Guillain-Barré syndrome. Currently, no vaccine or medication exists to prevent or treat Zika virus infection. Persons residing in or traveling to areas of active Zika virus transmission should take steps to prevent Zika virus infection through prevention of mosquito bites (http://www.cdc.gov/zika/prevention/).
Sexual transmission of Zika virus is possible, and is of particular concern during pregnancy. Current information about possible sexual transmission of Zika is based on reports of three cases. The first was probable sexual transmission of Zika virus from a man to a woman (6), in which sexual contact occurred a few days before the man’s symptom onset. The second is a case of sexual transmission currently under investigation (unpublished data, 2016, Dallas County Health and Human Services). The third is a single report of replication-competent Zika virus isolated from semen at least 2 weeks and possibly up to 10 weeks after illness onset; reverse transcriptase-polymerase chain reaction testing of blood plasma specimens collected at the same time as the semen specimens did not detect Zika virus (7). The man had no sexual contacts. Because no further testing was conducted, the duration of persistence of Zika virus in semen remains unknown.
In all three cases, the men developed symptomatic illness. Whether infected men who never develop symptoms can transmit Zika virus to their sex partners is unknown. Sexual transmission of Zika virus from infected women to their sex partners has not been reported. Sexual transmission of many infections, including those caused by other viruses, is reduced by consistent and correct use of latex condoms.
Suggested citation for this article: Oster AM, Brooks JT, Stryker JE, et al. Interim Guidelines for Prevention of Sexual Transmission of Zika Virus — United States, 2016. MMWR Morb Mortal Wkly Rep 2016;65(Early Release):1–2. DOI: http://dx.doi.org/10.15585/mmwr.mm6505e1er.
