Over 200 academics from around the world have now signed an open letter to the Director-General of the World Health Organisation (WHO) calling for the Olympics and Paralympics in Rio de Janeiro to be postponed or moved to another venue, owing to the threat posed by the ongoing Zika virus pandemic. The evidence concerning Zika virus so far, however, does not justify this course of action. The RioOlympicsLater.org authors misunderstand the nature of Zika virus, its history since its discovery in 1947, and also the relative risk posed by Zika virus versus other risks affecting any large event in a tropical country.