[1] Camden & Islington Community NHS Trust, London, England
[2] UCL, Dept Sexually Transmitted Dis & Virol, Royal Free & Univ Coll, Sch Med, London WC1E 6BT, England
[3] Univ Birmingham, Div Immun & Infect, PHLS Antiviral Susceptibil Reference Unit, Birmingham, W Midlands, England
[4] Birmingham Heartlands Hosp, Dept Sexual Med, Birmingham B9 5ST, W Midlands, England