The most extensive report yet on Zika virus and its risk to babies shows that 5 percent of women infected while pregnant go on to have babies with diagnosed birth defects.
Because data is fuzzy, this matches up with the last report showing 10 percent of women infected while pregnant have babies with birth defects.
The U.S. Centers for Disease Control and Prevention has recommendations online about traveling to or living in Zika-affected areas.
Mosquito season is heating up again in the northern hemisphere and the summer travel breaks start for many Americans. Here are some answers to some pressing questions about Zika, sex and pregnancy:
Can the virus be transmitted by any kind of sex?
Yes. “Sexual exposure includes vaginal sex, anal sex, oral sex, or other activities that might expose a sex partner to genital secretions,” the CDC says in its latest guidelines.
While male semen can be a source of transmission, there has also been at least one case of female-to-male transmission. The virus is mostly carried around by the Aedes mosquitoes, but it's becoming clear the virus can sometimes be transmitted by bodily fluids.
How do doctors know? It becomes clear if one sexual partner has traveled to a Zika-affected region and the other has not. And there's evidence the vagina may provide a good place for Zika virus to thrive.
What if I get infected now and want to get pregnant in a couple of years? Is my pregnancy at risk?
There is no evidence backing that up. The body clears the Zika virus eventually. There are some viruses that stay in the body permanently — herpes and the AIDS virus HIV, for example.
But Zika virus is one that the immune system eventually gets rid of. Several viruses are known to cause birth defects if the mother is infected during pregnancy. Rubella, also known as German measles, is an example. But there was never any evidence that women infected with rubella before they got pregnant had a higher risk of birth defects in later years.
Related: Zika Took Her Baby
How long do I have to wait before I get pregnant?
The CDC advises that people wait six months to try for a pregnancy if either partner has been to a Zika-affected area -- even if he or she doesn't have symptoms. If a woman is pregnant and her male partner could possibly have been infected, they should use a condom or abstain from sex for the whole pregnancy.
There’s a report of one man who had Zika virus in his semen more than six months after he showed symptoms of infection. Since nearly half of the pregnancies in the U.S. are unplanned, CDC also advises using a condom or abstaining from sex for six months if there's a chance a man has been infected with Zika.
"Men and women of reproductive age living in affected areas should be informed and orientated to consider delaying pregnancy," WHO advises.
What if I’m pregnant now and get bitten by a mosquito?
Not all mosquitoes carry Zika, even in the places where the virus is actively spreading. It’s the Aedes aegypti and Aedes albopictus mosquitoes that carry the virus, and one of them has to have bitten someone who’s infected — and even then, it takes a couple of days for the virus to build up enough in the mosquito’s body for the insect to transmit the virus to someone else.
So unless you are in an area where Zika is spreading, it’s not time to panic. Women in Zika zones need to take the strongest precautions, however and that includes using repellents such as DEET, covering up, and staying inside as much as possible. Women who become infected do need to see a doctor right away and get regularly tested and then have their pregnancy carefully monitored. There is no known way to protect a developing fetus from Zika infection, but doctors do know that not every woman who gets infected during pregnancy goes on to have a baby with birth defects.
If my baby is born normal, are we in the clear?
No one can say yet. The most obvious and horrifying birth defect known to be caused by Zika infection is microcephaly. The child’s head is smaller than normal because the brain itself is badly damaged. Doctors are now starting to report subtler birth defects in babies born to women who’d been infected. They include eye abnormalities, hearing defects and other brain damage. Some birth defects do not become apparent for years. The CDC is keeping a registry of all U.S. women who are pregnant and infected with Zika.