Nat. Med.; 10.1038/nm.4201; corrected online 15 November 2016

In the version of this article initially published online, the authors omitted acknowledging a funding agency and researchers for providing the pseudovirion neutralization assay data. The acknowledgments section has been revised to state, “We thank the US Army Medical Research Institute of Infectious Diseases team, including S. Kwilas, M. Wisniewski and J. Hooper, for providing the pseudovirion neutralization assay data used in this study. The pseudovirion work was funded by the US Department of Defense (DoD) Medical Countermeasures Systems' Joint Vaccine Acquisition Program at Fort Detrick, Maryland. The opinions, interpretations, conclusions and recommendations contained herein are those of the authors and are not necessarily endorsed by the US DoD.” The error has been corrected for all versions of this article.