New Study Suggests Zika Can Be Transmitted via Oral Sex

June 3rd 2016

Alex Mierjeski

People like to have sex. They also don't want to contract as-yet untreatable viruses such as Zika in the process. But according to new research, the two are becoming less and less mutually exclusive.

Oral sex

In a Thursday letter to the New England Journal of Medicine, scientists cited the case of a 26-year-old French woman who had both vaginal and oral sex with a 46-year-old man recently back from Rio de Janeiro, where he had experienced a fever, rash, and headaches — all known Zika symptoms.

Between the 11th and 20th of February, the two had sex seven times, during which they had vaginal sex without ejaculation and without a condom, and oral sex with ejaculation, scientists said. While the man had Zika in his semen and urine, he had none in his blood or saliva; the woman, however, had the virus in her saliva and urine, antibodies in her blood, but nothing in the results of a vaginal swab.

"We cannot rule out the possibility that transmission occurred not through semen but through other biologic fluids, such as pre-ejaculate secretions or saliva exchanged through deep kissing," the researchers wrote.

Teens making out

Sexual transmission of the Zika virus has been reported in multiple locations, including France, Germany, Italy, Portugal, and New Zealand, where mosquitos don't carry the virus. But the suggestion of oral transmission is new.

So just how sacred should we be of oral sex and swapping saliva?

Electron microscopy image of mosquito proboscis

John T. Brooks, an epidemiologist at the Centers for Disease Control and Prevention who studies Zika and sexual transmission, told The New York Times that he wasn't necessarily surprised that the virus might be transmissible via oral sex.

When it comes to transmission via kissing, however, Brooks added that "we'd have to look for deep kissing in the absence of sexual contact, and that's hard to find."

Kissy kissy

Others quoted in The Times noted that the discovery likely won't change much about recommended preventative measures or safety guidelines, but that it nonetheless highlights the unknowns still surrounding transmission of the virus.

In March, the Centers for Disease Control and Prevention issued suggestions for preventing sexual transmission of Zika. Those guidelines recommended avoiding all unprotected sex, including "mouth-to-penis oral sex." Until now, there was no known possible cases suggesting transmission via oral sex.

According to the CDC, experts still aren't sure if men without symptoms can pass Zika to a partner through their semen; or if a woman with Zika can pass it to a partner through vaginal or "mouth-to-vagina" oral sex.