As a long-term champion of open-access research data on pandemic viruses and a member of the Italian Parliament, I urge Brazil to hasten the reform of its current biosecurity legislation. This would enable sharing of vital Zika virus samples and information, as recently called for by the World Health Organization (see 10.1038/533469b, and go.nature.com/1o4x3dp).Data sharing for viruses has been disappointingly patchy since I first ignited the debate by depositing my unpublished sequence data for H5N1avian influenza virus in a public database, rather than in the established password-protected system (see 10.1038/440255b). When the 2009 H1N1swine flu virus emerged, the importance of data sharing was evident in the rapid response to the pandemic. However, the first isolate of the Middle East respiratory syndrome (MERS) coronavirus from Saudi Arabia was controversially submitted for patenting in 2013 (see go.nature.com/1uu7ldd). And in last year's Ebola virus epidemic, there were significant gaps in the availability and posting of online sequence data (10.1038/518477a).To overcome such hurdles, I suggest that the United Nations and relevant stakeholders should develop guidelines for scientists, institutions and governments. These should harmonize codes of conduct on sharing information about emerging biological threats — including pathogens that are resistant to antimicrobials.