Updated on August 6, 2024.
While women of childbearing age rightfully worry about getting Zika—the mosquito-borne virus linked to microcephaly and other severe birth defects—many men have been left to wonder if they should be worried, too.
The answer is yes.
Researchers know that Zika is not a gender-specific illness, and that men should be just as cautious as women when it comes to protecting themselves and others from the virus.
Men and Zika
The biggest threat Zika poses for a man lies in his ability to, unknowingly, transmit the virus through sex, says infectious disease specialist David Itkin, MD, of Portsmouth Regional Hospital in New Hampshire. In fact, sexual transmission is one of the defining characteristics of the virus.
“A man could’ve traveled to Brazil, or another Zika area, gotten a symptomatic or asymptomatic infection, come back, and now he poses a risk to a pregnant woman because he could transmit the virus to her sexually,” Dr. Itkin explains. “This is a woman who may never have been out of the country, never traveled to an area where Zika is circulating.”
Researchers still don’t know how long Zika can remain in semen, which means doctors can’t say how long a man is contagious. Worst-case scenario, the man has no symptoms and is contagious for months without ever knowing he was infected, says Itkin.
This is worrisome because once infected, the man can potentially transmit the virus to a pregnant woman who could then transmit Zika to her developing baby.
“The man could be a symptom-free carrier of Zika and, indirectly, cause a congenital defect,” he says.
Outside of sexual transmission, says Itkin, the virus itself doesn’t pose a big risk to a man’s health. If he has symptoms, such as fever or rash, they are typically mild.
Zika has also been linked to Guillain-Barré syndrome (GBS), a disease of the nervous system that can cause muscle weakness or temporary paralysis, but the risk appears to be very small, Itkin says. Many other viruses can cause the same problems.
Female-to-male transmission?
According to the Centers for Disease Control and Prevention (CDC), it appears to be possible for a woman to spread Zika to a man, as well.
Based on what we know, a woman may potentially transmit Zika to a male partner during sex as long as the virus remains in her blood.
Transmission through anal or oral sex also appears to be possible. The virus is present in saliva, too, but there’s no evidence thus far that Zika can spread through kissing.
Men need to be informed
While there's still a lot left to learn about Zika, it's clear is that doctors should talk to their male patients about the disease.
“As we see men traveling to Zika areas, we’re going to have to have that talk with them,” says Itkin. “You went on this trip. You were fine and healthy and didn’t get sick. You don’t even think you saw a single mosquito."
"That’s all well and good," Itkin adds, "but there’s still a chance—and a chance you need to take seriously—that you could’ve become exposed and may be contagious via sex for months to come.”
Protecting yourself from Zika
- Both men and women should take precautions against mosquito bites, especially when in an area with known Zika transmission. The CDC recommends using insect repellents with active ingredients including DEET, picaridin, IR3535, oil of lemon eucalyptus, para-menthane-diol or 2-undecanone. According to the CDC, these ingredients are safe and effective for pregnant and breast-feeding women when used as directed. Other important steps to reduce Zika risk: cover up when you are outside, keep property free of standing water and ensure window screens fit properly.
- Women who are pregnant should avoid traveling to areas with risk of Zika.
- Women who have traveled to an area with risk of Zika should wait at least two months after potential exposure before trying to get pregnant.
- Men who have traveled to a Zika area should wait at least six months before having unprotected sex, whether or not they’ve had any symptoms of Zika infection.
- Sexually active men who live in or have traveled to an area with Zika and are worried about sexual transmission should wear condoms every time they have sex—including during vaginal, anal and oral sex—and especially if a partner is pregnant.
- The best way to avoid transmission of Zika to a developing baby is to not have sex during the pregnancy.
Above all, the CDC advises that men or women who live in or travel frequently to areas with risk of Zika should speak with their healthcare providers about pregnancy plans, their risk of Zika infection and ways to protect against the virus.