The World Health Organization has estimated that in the next year, the Zika virus will infect up to 4 million people across the Americas. The mosquito-borne disease is associated with microcephaly, a neurological disorder in which babies are born with abnormally small heads. Here, what the Zika virus has to do with sex, kissing, blood transfusions, and organ transplants.
1. Can I actually get Zika from having sex?
Yes. Based on three separate cases, sexual transmission of Zika virus through semen is possible. In one recent case, the Dallas County Health and Human Services Department reported that someone who traveled to Venezuela, an affected country, infected a patient through sexual intercourse. Scientists are unsure if sexual transmission is possible if infected men never develop symptoms (in each of the three cases, the men had symptomatic illness) or exactly how long the virus persists in semen. The virus may be detectable in semen even when it is no longer detectable in blood. So far, there have been no reported cases of women passing Zika to sexual partners.
If men with pregnant partners travel to an affected country, the CDC recommends they use latex condoms vigilantly or abstain from insertive sex completely until the baby is born. The guidelines stress this refers to any type of insertive sex (vaginal, anal, and oral).
“We don’t have a lot of answers as to why the Zika virus may be in seminal fluid longer than in blood,” says Mindy Christianson, MD, a reproductive endocrinologist and assistant professor at Johns Hopkins School of Medicine. “As a result, we want to be as cautious as possible.”
If you’re pregnant, discuss your partner’s potential exposure and history of symptoms with a doctor.
2. What if a man doesn’t have a pregnant partner?
In that case, it’s a personal decision. The CDC states any men who have traveled to an affected area and who are concerned about sexual transmission might consider following the same guidelines as men with pregnant partners: sex with careful condom use or no sex at all. However, the CDC does note Zika virus symptoms are often mild—if any appear (80 percent of people infected with Zika never have symptoms). The biggest risk is to pregnant women.
3. If Zika can be transferred through semen, are sperm banks safe?
Probably. The American Fertility Association has not issued guidelines on preventing Zika virus in sperm banks. The British Fertility Society, however, recommends individuals who have traveled to affected areas should not undergo fertility treatments or donate sperm or eggs for 28 days.
“Sperm banks can set up their own policies as far as whether they’ll accept sperm,” says Dr. Christianson. “But the FDA heavily regulates sperm banks, so there are already measures in place [to prevent disease].” Sperm banks must keep donations in frozen quarantine for six months to ensure the sperm is free of disease (it can take this long to detect HIV in blood, for example).
Certain clinics throughout the country have taken additional measures to protect against Zika virus. California Cryobank, a nationwide sperm bank, has adopted a policy to not accept sperm donations from men who have traveled to affected countries in the past month. It also does not accept donations from men who have had sex with someone who traveled to an affected area in the past month.
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4. If I’m pregnant, should I worry about getting Zika virus from kissing?
The CDC doesn’t warn against kissing. One test found the Zika virus in saliva and urine, but it’s not proof that a transmission can occur. The test looked for genetic material, which is unlikely to cause an infection (similar to how HIV is also found is saliva, but saliva cannot transmit the HIV virus).
Last week, however, a Brazilian health official warned pregnant women to take special precautions: Only kiss a regular partner and don’t share cutlery, plates, and glasses with people who have Zika symptoms. The recommendation came at the beginning of Brazil’s Carnival, a five-day celebration in which kissing strangers is a common part of festivities.
“We take all reports seriously,” said Tom Frieden, director of the CDC, in a news briefing. “We would need more information about that report [that found the Zika virus in saliva], including the methodology of it.”
5. Since Zika is transmitted through blood, are blood transfusions safe?
Brazil has reported two cases of Zika virus transmission through blood transfusions. Precautions are being taken to keep blood banks in the United States safe. “We wouldn’t be surprised to see occasional transfusion-associated cases if someone gave blood when the virus was in their blood,” said Frieden.
Because of that risk, the American Association of Blood Banks (AABB) has issued recommendations to defer blood donations from individuals who have traveled to an affected area in the past 28 days. The American Red Cross is following the AABB’s guidelines and also asks donors to immediately notify the Red Cross if he or she develops symptoms consistent with Zika virus within 14 days of donating. In these cases, the Red Cross will quarantine the donation.
“The risk of contracting Zika by blood transfusion in the continental U.S. at this time is believed to be extremely low due to the absence of local mosquito transmission,” said Susan Stramer, PhD, vice president of Scientific Affairs at the American Red Cross, in a statement. “The Red Cross continues to use additional safety measures to protect the blood supply from Zika.”
6. Can organ transplants transmit Zika virus?
Scientists aren’t sure. Transplant centers should balance the risk of Zika infection with the possible benefits in someone who needs an organ transplant, according to a statement from multiple leading transplant groups.