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CDC: Zika May Have Been Sexually Transmitted in 14 Cases

Virus transmission through sexual activity now appears “more likely,” agency says

The Centers for Disease Control and Prevention (CDC) and state public health departments are investigating 14 new reports of possible sexual transmission of Zika virus, including several involving pregnant women.

On February 5, the CDC published interim recommendations for protecting people against the sexual transmission of Zika virus. This guidance was issued after laboratory confirmation of Zika virus infection in a U.S. nontraveler that was linked to sexual contact with an infected partner.

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 a 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 from the immunoglobulin M (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, the travelers were men who reported symptom onset within two weeks before the nontraveling 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, the CDC says.

Although sexual transmission of Zika virus infection is possible, mosquito bites remain the primary way that Zika virus is transmitted. Because there 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 that sexual transmission may be a more likely means of transmission for Zika virus than previously considered, the CDC has issued a health advisory notice to underscore the importance of adhering to the interim guidance published on February 5.

The CDC’s interim guidance includes the following recommendations for pregnant women and for men with pregnant sex partners who live in or have traveled to Zika-affected areas:

  • Pregnant women and their male sex partners should discuss the male partner’s potential exposures and history of Zika-like illness with the pregnant woman’s health care provider. Providers should consult the CDC’s guidelines for the evaluation and testing of pregnant women.
  • Men with a pregnant sex partner who reside in or have traveled to an area of active Zika virus transmission and their pregnant sex partners should use condoms during sex (vaginal, anal, or oral) or abstain from sexual activity for the duration of the pregnancy. Using latex condoms reduces the risk of sexual transmission of many infections, including those caused by other viruses.

The CDC’s interim guidance also includes the following recommendations for nonpregnant women and men with nonpregnant sex partners who live in or have traveled to Zika-affected areas:

  • Couples in which a man resides in or has traveled to an area of active Zika virus transmission who are concerned about the sexual transmission of Zika virus may consider using condoms during sex or abstaining from sexual activity.
  • Couples may consider several factors when making the decision to use condoms or to not have sex: 1) Zika virus illness is usually mild. An estimated four out of five people infected never have symptoms; when symptoms occur they may last from several days to one week. 2) The risk of Zika infection depends on how long and how much a person has been exposed to infected mosquitoes, and the steps taken to prevent mosquito bites while in an affected area.
  • The science is not clear on how long the risk should be avoided. Research is under way to answer that question. If a woman is trying to get pregnant, she may consider Zika virus testing in her discussion with her health care provider.

Source: CDC; February 23, 2016.

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