Nat. Immunol. 13, 423–427 (2012); published online 18 April 2012; corrected after print 19 April 2012

In the version of this article initially published, the second sentence of the abstract and reference 9 were incorrect. That second sentence should read “Correlates of risk of infection for the RV144 trial have been found.” Reference 9 should read “Haynes, B.F. et al. N. Engl. J. Med. 366, 1275–1286 (2012).” The errors have been corrected in the HTML and PDF versions of the article.