[1] Barts & London Queen Marys Sch Med & Dent, Blizard Inst Neurosci Surg & Trauma, London, England
[2] Royal London Hosp, Dept Emergency Med, Whitechapel Rd, London E1 1FR, England
[3] Barts Hlth NHS Trust, London, England
[4] Beth Israel Deaconess Med Ctr, Dept Emergency Med, Boston, MA USA
[5] Harvard Med Sch, Boston, MA USA
[6] Johns Hopkins Univ, Bloomberg Sch Publ Hlth, Dept Mol Microbiol & Immunol, Baltimore, MD USA