Men potentially exposed to Zika virus should use a condom during all sex or abstain from sex for at least 8 weeks, according to new recommendations from the Centers for Disease Control and Prevention on reducing the risk of sexual transmission of the virus.

Men with confirmed infections or clinical symptoms of Zika should similarly abstain or use a condom for at least 6 months, the CDC recommends in the Morbidity and Mortality Weekly Report released on March 25 (MMWR 2016. Mar 25. doi: http://dx.doi.org/10.15585/mmwr.mm6512e3er).

These recommendations update and replace those issued by the CDC on Feb. 5 and include new guidance for men who live in, or have traveled to, an area with active Zika virus transmission. The recommendations apply to all types of sexual activity involving the penis, including vaginal intercourse, anal intercourse, or fellatio.

“The previous recommendations focused on women who were already pregnant,” Dr. Denise J. Jamieson, co-lead of the Pregnancy and Birth Defects Team of the CDC Zika Virus Response Team, said during a press briefing. “What’s new is that we are now concerned about the periconceptional period, around the time the woman conceives.”

For men with pregnant sex partners, the agency recommends consistent and accurate use of condoms during any type of sex, or abstinence during the length of the pregnancy.

“This course is the best way to avoid even a minimal risk of sexual transmission of Zika virus, which could have adverse fetal effects when contracted during pregnancy,” the CDC report states, adding that pregnant women should ask their male sex partners about recent travel to areas with currently circulating Zika virus.

For couples not expecting a child, but concerned about sexual transmission of Zika, men with a confirmed Zika infection or clinical symptoms of Zika infection should consider using condoms or abstaining from sex for at least 6 months after their symptoms appear. This recommendation is based on tripling 62 days – the longest time interval after infection during which the virus was successfully isolated from semen.

If men have traveled to areas with active Zika transmission but have not developed symptoms, the CDC recommends condom use or abstinence for at least 8 weeks after leaving the area. Those living in areas with active transmission should also consider condom use during sex or abstaining from sex until active transmission has ceased.

These recommendations come as more evidence points to a link between Zika infection and fetal abnormalities, including microcephaly and fetal mortality.

“I think we’re learning more every day, and I think the evidence of a link between Zika and a range of poor pregnancy outcomes is becoming stronger and stronger,” Dr. Jamieson said. “At this point, we’re not using causal language, but the evidence is mounting.”

The CDC also released two other reports focusing on the need to increase access to contraception for residents of Puerto Rico and interim guidance for health care providers of women of childbearing age who have been potentially exposed to Zika virus.

As of March 25, the CDC has reported 273 U.S. cases of Zika virus infections from 35 states and Washington, D.C. All of these – except six sexually transmitted cases – are travel related.

Additionally, Puerto Rico’s most recent case total is 261, all locally transmitted by mosquitoes, except for three travel-associated cases. American Samoa has 14 cases, and the U.S. Virgin Islands have 11 cases, all thought to be locally transmitted.

“Long-acting contraception methods are not readily available in Puerto Rico, and from our health care provider colleagues in Puerto Rico, there is a desire to provide a more broad range of contraception options to women in Puerto Rico,” Dr. Jamieson said.

She said the CDC is developing a plan to make long-acting contraceptive methods more available in Puerto Rico.

When advising couples who wish to become pregnant after the man has had confirmed or suspected Zika infection, the CDC recommends waiting at least 6 months after the man’s onset of Zika symptoms or confirmed infection before attempting to conceive.

Although no evidence suggests that Zika virus will cause congenital infections in pregnancies conceived after a woman’s infection has resolved, data on the virus’s incubation period is limited, according to the CDC.

“Women with Zika virus disease should wait until at least 8 weeks after symptom onset before attempting conception,” wrote Dr. Emily E. Petersen and her colleagues in the guidance on caring for women of reproductive age with possible Zika virus exposure. “No data are available regarding the risk for congenital infection among pregnant women with asymptomatic infection.”

Similarly, asymptomatic women potentially exposed to Zika virus should also wait at least 8 weeks after the possible exposure date before trying to conceive.

CDC updates advice on preventing sexual transmission of Zika virus