Baseline demographic characteristics of subjects enrolled in international quadrivalent HPV (types 6/11/16/18) vaccine clinical trials
BACKGROUND: In Phase II/III trials, administration of quadrivalent human papillomavirus (HPV) (types 6/11/16/18) L1 virus-like-particle vaccine was highly effective in preventing HPV6/11/16/18-related cervical intraepithelial neoplasia and non-invasive cervical cancer in women aged 16-26 years who were naïve to these HPV types at enrollment. However, the makeup and extent of catch-up vaccination p