• Safety, as determined by development of Grade 3 or 4 adverse events (AEs) [ Time Frame: Throughout study ] [ Designated as safety issue: Yes ]
  
• safety, as determined by development of Grade 3 or 4 AEs attributed to study treatment [ Time Frame: throughout study ] [ Designated as safety issue: Yes ]
  
• immunogenicity, as determined by anti-HPV 6, 11, 16, 18 responses measured by Clinical Laboratory Improvement Act (CLIA) [ Time Frame: at Week 28 ] [ Designated as safety issue: No ]
  
• serum antibody titers [ Time Frame: throughout study ] [ Designated as safety issue: No ]
  

• Change in CD4 count and percent [ Time Frame: throughout study ] [ Designated as safety issue: No ]
  
• change in viral load (HIV-1 RNA copies/ml) [ Time Frame: throughout study ] [ Designated as safety issue: No ]
  

Genital HPV infection is the most common sexually transmitted infection in the world and may lead to genital warts, anogenital dysplasias, and invasive cancers. HIV infected people and others with compromised immunity are at greater risk for HPV-related complications. In particular, researchers are concerned about the risk of HPV infection to women, who may be infected by their male partners, especially if these partners engage in anal intercourse. HIV infected women tend to have multiple types of HPV (associated with a greater risk of HPV-related disease), are less likely to clear HPV-related conditions, and are more likely to progress to HPV-related disease. The quadrivalent HPV (types 6, 11, 16, 18) L1 virus-like particle (VLP) vaccine to be tested in this study was safe and generally well tolerated in previous studies conducted in healthy and HPV-exposed adolescents, young adults, and older women. However, it is still unclear if the vaccine will be safe and will elicit a similar immune response in younger children. The purpose of this study is to evaluate the safety and immunogenicity of the novel quadrivalent HPV (Types 6, 11, 16, 18) L1 VLP vaccine in HIV infected children 7 to 12 years of age.

This study has two stages and will last at least 108 weeks. In Stage I, participants will be randomly assigned to one of two groups; within their group, they will be stratified by CD4 count percentage (CD4%) nadir and CD4% at study screening. During Stage I, Group 1 participants will receive 3 doses of vaccine, while Group 2 participants will receive 3 doses of placebo. Participants will not know whether they are receiving vaccine or placebo. Participants will receive their assigned intervention at study entry and Weeks 8 and 24. At Week 96, Stage II will begin, and all study participants will be told if they received vaccine or placebo in Stage I. Group 1 participants will receive an additional dose of vaccine at Week 96; Group 2 will receive doses of vaccine at Weeks 96, 104, and 120. Over the course of the study, there will be at least 12 study visits. A physical exam and blood collection will occur at most visits; medical history will occur at selected visits.

After each vaccination, participants will be observed for at least 30 minutes to monitor for any allergic reactions possibly resulting from the vaccination. For 15 days following vaccination, parents or guardians will be asked to complete a "report card" with details of each child's signs and symptoms. Three days after each vaccination, parents or guardians of study participants will be contacted by telephone and asked about any adverse events that a child may have experienced.