New research shows women potentially can spread Zika virus to sexual partners for up to six months after infection

April 18, 2019

Women who are infected with the Zika virus potentially can spread the virus to sexual partners for up to six months after infection. This finding prolongs the period of time following acute infection that the virus was known to be present in vaginal secretions.

Dr. Sylvia Becker-Dreps

Sylvia Becker-Dreps, MD, MPH, associate professor in the Department of Epidemiology at the UNC Gillings School of Global Health, is co-author of the paper “Prolonged Shedding of Zika Virus RNA in Vaginal Secretions, Nicaragua,” which was published in the April 2019 issue of Emerging Infectious Diseases, a publication of the Centers for Disease Control and Prevention (CDC).

“Though we knew Zika had been detected in vaginal secretions, our study found that the virus could still shed into secretions for a longer period of time than previously thought – in one of the five women, for up to 180 days,” says Becker-Dreps, who is the director of the UNC Program in Nicaragua. “The CDC currently says women in Zika endemic areas should not try to conceive for two months following infection, but our study shows that vaginal shedding lasts for longer than that period of time.”

The study followed five Nicaraguan women identified in the acute infection phase of the Zika virus. Participants used swabs to collect specimens of vaginal secretions to be tested for presence of the virus. Of the five women, one still showed the virus in a sample taken at 180 days past infection, compared with results showing a final positive sample between 21 and 60 days for the other four participants. These are serious findings, as they clarify the potential for sexual transmission of the Zika virus, or possibly, ascending fetal infection in a pregnant woman.

As acute Zika infections are difficult to capture and samples are not easy to collect, viral shedding of Zika in the female genital tract had not been widely reported. While this testing found the presence of viral RNA, it was unable to show if the sample was infectious.

The areas of the world where the Zika virus is considered to be endemic change, but the virus itself is not going away, says Becker-Dreps.

“In Nicaragua, the epidemic has now gone away, but there was a new outbreak in India at the end of 2018. The mosquito vector has a broad range, and we will continue to see outbreaks.”

Becker-Dreps holds an appointment as associate professor in the UNC School of Medicine’s Department of Family Medicine. Another UNC author on the paper is the School of Medicine’s Natalie Bowman, MD, MPH, an assistant professor in the Division of Infectious Diseases. Bowman is part of UNC’s Infectious Disease Epidemiology and Ecology Lab, which was formed in 2015 with the mission of better understanding prevalent infectious diseases in order to improve the health of the world’s poorest populations. The study was conducted with scientific collaborators at the University of Nicaragua, León.

Contact the Gillings School of Global Public Health communications team at sphcomm@listserv.unc.edu.