In light of the latest scientific findings about Zika virus, the US Centers for Disease Control and Prevention (CDC) fine-tuned its guidance for counseling pregnant women and preventing sexual transmission of the virus, and it also addressed reducing unintended pregnancies, using lessons from Puerto Rico's outbreak.
The CDC released the updates today at a media briefing and published the details in three separate reports in Morbidity and Mortality Weekly Report (MMWR). In a press release the CDC said it will continue to update its guidance to reflect accumulating evidence, expert opinion, and knowledge about the risks that come with other viral infections.
Pregnancy planning specifics
Denise Jamieson, MD, MPH, who co-leads the CDC's pregnancy and birth defects team and its Zika response team, said evidence is mounting regarding the link between Zika virus, microcephaly, and other birth outcome problems. "The rate is not known, but we're studying it," she said.
The biggest change in the guidance is the inclusion of suggested waiting times for women who are trying to become pregnant, on the basis of symptoms, travel history, and sexual contact history.
Women with confirmed or suspected Zika virus infections should wait at least 8 weeks until after the first symptoms appeared before trying to conceive, the CDC said. Male partners who are diagnosed or have symptoms compatible with Zika virus should wait at least 6 months before having unprotected sex.
The CDC said it based the length of the waiting periods on the longest known risk period for the two patient categories and allowed for three times the known period of time.
Women and men who have no symptoms but may have been exposed during travel or sexual contact should wait 8 weeks before getting pregnant, the CDC advised.
Couples who live in areas with local transmission should talk with their doctors about pregnancy planning during the outbreak, the risks of Zika infection, and how to avoid mosquito bites, the CDC advised, acknowledging that conception timing decisions are "complex, deeply personal decisions."
Safe-sex timelines for avoiding infection
The main change to the CDC Zika sexual transmission guidance was the addition of condom or abstinence time periods, but for the first time the CDC said its recommendations also apply to men and their male sex partners. So far there is no evidence that women can transmit the virus through sexual contact.
The CDC has confirmed six sexual transmission cases so far. In a related development, the California Department of Public Health (CDPH) announced its first sexual transmission case. It said in a statement that the infected woman had not traveled outside the country and was not pregnant and that she and her partner, who had returned from a Zika-hit country, have fully recovered.
Couples including men who have confirmed or suspected Zika infection should consider using condoms or abstaining for at least 6 months after the start of symptoms. Couples with men who weren't sick but traveled to an area where Zika virus is circulating should take the same safe-sex steps for at least 8 weeks to minimize the risk, the CDC said.
Meanwhile, couples including men who live in Zika-affected areas should consider using condoms or abstaining from sex while the virus is circulating, and those who are considering pregnancy should consult their healthcare providers, according to the updated guidance.
Contraception considerations in Zika-hit countries
The CDC said strategies to prevent unplanned pregnancies are critical for preventing Zika virus complications, and that Puerto Rico's experience points to problems with access to effective birth-control methods. The agency said about two-thirds of the territory's pregnancies are unintended and estimated that 138,000 Puerto Rican women may be at risk.
Women and their partners in local transmission areas should be advised about the range of effective options and taught how to correctly and consistently use them, the CDC said, adding that the Department of Health and Human Services is exploring ways to use existing programs to improve access to contraception in Puerto Rico.
See also:
Mar 25 CDC press release
Mar 25 MMWR report on updated guidance for care of childbearing-age women with possible Zika exposure
Mar 25 MMWR report on updated CDC guidance for preventing Zika sexual transmission
Mar 25 CDPH statement
Mar 25 MMWR report on estimating contraceptive needs in Puerto Rico
