[1] Univ Hosp Leicester NHS Trust, Clin Microbiol, Leicester Royal Infirm, Level 5 Sandringham Bldg,Infirm Sq, Leicester LE1 5WW, Leics, England
[2] Univ Hosp Leicester NHS Trust, Infect Dis Unit, Leicester, Leics, England
[3] Univ Leicester, Dept Resp Sci, Leicester, Leics, England
[4] Erasmus MC, Dept Virosci, Rotterdam, Netherlands