WHO published interim guidelines on the prevention of sexual transmission of Zika virus in September 2016 (1), based on a limited amount of evidence under an emergency process during a public health emergency of international concern. The body of evidence has grown considerably since then and WHO experts concluded, at a meeting in March 2017, that the guidelines should be developed under the formal WHO guideline process (2). These guidelines contain updated recommendations on the prevention of sexual transmission of Zika virus, based on the best available evidence as of June 2018.