Note: Knowledge about Zika virus and health complications associated with infection is still evolving and this page will be updated as new information is released. Content on this page was last updated October 5, 2016.
Zika is a virus that is passed on to humans through the bite of an infected Aedes species mosquito. Once infected, a person can pass on Zika through sexual activity–including vaginal, oral and anal sex and the sharing of sex toys. Zika can also be passed on by a mother to her fetus during pregnancy, and Zika infection during pregnancy has been linked to a serious birth defect called microcephaly as well as other poor pregnancy outcomes.
You’ve likely heard about Zika virus in the news of late. While Zika was first identified in human in 1952 in Uganda, it has been largely unknown in the U.S. until recently. A Zika outbreak that was first reported in Brazil in 2015 has now spread to several countries in South America and the Caribbean. While Zika is not widespread in the continental U.S. at this point, there have been more than 3,500 cases reported among travelers and their sexual partners. The only state where there have been locally-acquired cases of Zika from mosquito bites is Florida. As of September 28, 2016, there have 59 of these cases identified in Florida.
Sexual Transmission of Zika
Zika can be passed through vaginal, oral and anal sex, even if the person does not have symptoms at the time. It can be passed from a person with Zika before their symptoms start, while they have symptoms, and after their symptoms end. Recent evidence suggests that Zika can also be transmitted sexually even if a person has no symptoms. The CDC reported on a case where Zika was likely transmitted sexually from a man to his female partner, even though they man displayed no symptoms of infection. Condoms—including both male and female condoms—can reduce the chance of getting Zika from sex.
According to the Centers for Disease Control and Prevention (CDC), 30 cases of Zika virus infection transmitted by sexual contact had been reported in the United States as of September 28, 2016. In these cases, at least one partner had traveled to an area where Zika transmission is active, been infected, and passed the virus on to a partner.
The Centers for Disease Control and Prevention (CDC) has updated its pre-pregnancy counseling and guidance for the prevention of sexual transmission of Zika virus:
- Both men and women who are considering becoming pregnant may want to avoid nonessential travel to areas where Zika is actively transmitted.
- Asymptomatic men with possible Zika exposure are advised to abstain from sex or to use condoms for at least six months to protect against Zika transmission (the previous recommendation was eight weeks)
- The amount of time couples should wait to try and conceive if the man has possible Zika exposure but no symptoms has also increased from eight weeks to a minimum of six months.
CDC continues to advise women with possible Zika exposure who don’t live in an area of active transmission to wait at least eight weeks before becoming pregnant. CDC’s complete guidance on protecting yourself from Zika during sex is available here.
Symptoms of Zika Infection
Most people infected with Zika don’t have any symptoms at all. Those who do might experience mild illness with fever, rash, joint pain, and red eyes as the most common symptoms lasting for a week or less.
Zika and Pregnancy
There have been reports a serious birth defect of the brain called microcephaly and other poor pregnancy outcomes in babies of mothers who were infected with Zika virus while pregnant. But what is still not known is how likely it is that Zika will pass to a woman’s fetus, and whether or not an infected fetus will develop birth defects.
The CDC has established the US Zika Pregnancy Registry to collect information about pregnancy and infant outcomes following laboratory evidence of Zika virus infection during pregnancy. As of September 22, 2016, the registry reports 808 pregnant women with laboratory evidence of possible Zika infection in the U.S., and 1,490 pregnant women in U.S. territories. The registry also reports 21 infants born with birth defects born to Zika-infected mothers in the U.S., as well as 5 pregnancy losses. The CDC will be following the pregnancy outcomes to learn more about the growth and development of babies whose mothers had Zika while pregnant.
Prevention for Pregnant Women
Until experts know more about the nature of Zika virus, the Centers for Disease Control and Prevention (CDC) has recommended that pregnant women not travel to any area where Zika virus is spreading. If you must travel to one of these areas, CDC recommends that you talk to your doctor or healthcare provider first and strictly follow steps to prevent mosquito bites during the trip. CDC also recommends that pregnant women either not have sex during their pregnancy or use condoms consistently if their male partners travel to or live in an area where Zika virus is actively being transmitted. See the CDC website for details on these recommendations.
While Zika is can be transmitted through sex, there are of course a number of infections that are sexually transmitted as well. CDC recommends all pregnant women be tested on their first prenatal visit for chlamydia, gonorrhea, syphilis, and hepatitis B. Read ASHA’s page on Women & STIs for more and remember that condoms are a reliable way to prevent STIs and unintended pregnancy. Take a look at these other resources and take charge of your sexual health!
- Reduce Your Risk
- How Do STI Tests Work? Which Ones are Right for Me?
- CDC’s Find a Testing Location Tool