Federal health officials are advising men who have possibly been exposed to Zika virus to practice safe sex and delay plans for conception for at least 6 months after exposure.
The Centers for Disease Control and Prevention updated its recommendations for preventing sexual transmission of the Zika virus and its preconception guidance, extending the time frame that men should abstain from unprotected sex to prevent transmission.
Previously , only symptomatic men were advised to wait 6 months before trying to conceive a child, while asymptomatic men had to wait only 8 weeks from last possible exposure. Now, men who have been exposed to the virus should either abstain from sex or use a condom to prevent sexual transmission of the disease for at least 6 months, even if they are asymptomatic. Men who are trying to have a child with their partner should also wait at least 6 months.
For now, recommendations for women have not been changed. Women who have been exposed to Zika virus should wait at least 8 weeks after symptom onset (if symptomatic) or last possible exposure to the virus before attempting to conceive. Women who do not plan to become pregnant but live in, or travel to, Zika-endemic regions should either abstain from sex or use the best possible protection available to them ( MMWR. 2016 Sep 30. doi: 10.15585/mmwr.mm6539e1 ).
“Two new reports describe one presumed and one more definitive case of sexual transmission from men with asymptomatic Zika virus infection to female sex partners,” Emily E. Peterson, MD, of the CDC’s Zika response team, and her colleagues wrote in the Morbidity and Mortality Weekly Report. “Among reported cases of sexually transmitted Zika virus infection, the longest reported period between sexual contact that might have transmitted Zika virus and symptom onset was 32-41 days (based on an incubation period of 3-12 days).”
Zika virus can be transmitted through either vaginal, anal, or oral sexual intercourse. While Zika virus RNA decreases over time after the infection passes, it can linger in semen for as long as 188 days after symptom onset, according to the CDC.
For nonpregnant women, Zika virus RNA has been detected in serum for up to 13 days post-onset of symptoms, and for 58 days in whole blood samples. For pregnant women, it can be detected in serum for as long as 10 weeks after the onset of symptoms.
“Detection of Zika virus RNA in blood might not indicate the presence of infectious virus, and thus the potential risk for maternal-fetal Zika virus transmission periconceptionally is unknown,” the researchers wrote.