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Living systematic review describes the epidemiology of sexual transmission of Zika virus


Zika virus (ZIKV) may be sexually transmissible for a shorter period than previously estimated, according to a systematic review published this week in PLOS Medicine by Michel Counotte and Nicola Low of the University of Bern in Switzerland, and colleagues. The review included analysis of data from both human and animal studies and was conducted to describe the epidemiology of sexual transmission of ZIKV.

Sexual transmission of ZIKV has been previously documented, but the risks of transmission are not well understood, and it is not known whether other flaviviruses can be transmitted this way. To address this gap in knowledge, the researchers conducted a systematic review of available, relevant evidence through 15 April 2018. Counotte and colleagues found that, where documented, sexual transmission of ZIKV is much more common from men to women than from women to men. For sexual transmission of ZIKV, the authors found the median serial interval--the time between onset of symptoms in 2 sexual partners--is 12 days, and the median duration of ZIKV RNA persistence in semen is longer (34 days) than in the female genital tract (12 days). They found no evidence of sexual transmission for any other arthropod-borne flaviviruses.

The study's conclusions are limited by the underlying evidence, which may have residual biases. However, the review is constructed as a living systematic review, such that newer evidence will be integrated upon availability. Of public health relevance, the authors state, "our findings suggest that the infectious period for sexual transmission of ZIKV is shorter than estimates from the earliest post-outbreak studies."


Research Article


MJC and JW received salary support from Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung (CH) Award Number: 320030_170069 & 320030_176233. MJC received salary support from World Health Organization contracts 2017/725385-0 and 2017/733494-0. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Competing Interests:

I have read the journal's policy and the authors of this manuscript have the following competing interests: NL receives a stipend as a Specialty Consulting Editor for PLOS Medicine, and serves on the journal's editorial board.


Counotte MJ, Kim CR, Wang J, Bernstein K, Deal C, Broutet NJN, et al. (2018) Sexual transmission of Zika virus and other flaviviruses: A living systematic review. PLoS Med 15(7): e1002611.

Image Credit: NIAID, Flickr

Author Affiliations:

Institute of Social and Preventive Medicine, University of Bern, Bern, Switzerland

Department of Reproductive Health and Research, World Health Organization, Geneva, Switzerland

Division of Sexually Transmitted Disease Prevention, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America

National Institute of Allergy and Infectious Diseases, Rockville, Maryland, United States of America

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