The human papillomavirus (HPV) infection is the primary cause of cervical cancer, a major public health concern in sub-Saharan Africa (SSA). In Tanzania, two prophylactic HPV vaccines are licensed to prevent infection with the HPV types associated with the majority of cervical, anal and oral cancers. Scale-up of national HPV vaccination programmes in low-income countries has been slow, partly because of the costs to deliver two or three doses of the HPV vaccine to pre-adolescent and adolescent girls. The aim of this trial is to establish whether a single dose of HPV vaccine produces immune responses that are likely to be effective in preventing cervical cancer in SSA.