On February 5, 2016, the CDC published interim recommendations for protecting people against sexual transmission of Zika virus.
This guidance was issued after lab confirmation of the first case of Zika virus infection in a non-traveler in the continental United States, which was linked to sexual contact with an infected partner.
CDC and state public health departments are now investigating 14 new reports of possible sexual transmission of Zika virus, including several involving pregnant women. In two of the new suspected sexual transmission events, Zika virus infection has been confirmed in women whose only known risk factor was sexual contact with an ill male partner who had recently traveled to an area with local Zika virus transmission; testing for the male partners is still pending.
For four additional suspected sexual transmission events, preliminary laboratory evidence (IgM antibody test) is available for the women, but confirmatory tests are pending. For eight other suspected events, the investigation is ongoing. In all events for which information is available, travelers were men and reported symptom onset was within 2 weeks before the non-traveling female partner’s symptoms began. Like previously reported cases of sexual transmission, these cases involve possible transmission of the virus from men to their sex partners. At this time, there is no evidence that women can transmit Zika virus to their sex partners; however, more research is needed to understand this issue.
Although sexual transmission of Zika virus infection is possible, mosquito bites remain the primary way that Zika virus is transmitted. Because there currently is no vaccine or treatment for Zika virus, the best way to avoid Zika virus infection is to prevent mosquito bites.
Because these new reports suggest sexual transmission may be a more likely means of transmission for Zika virus than previously considered, CDC issued a Health Advisory Notice (HAN) today to underscore the importance of adhering to the interim guidance published on February 5.