Immunogenicity and Safety of HPV-4 Vaccine With or Without Td Vaccine in Children

This study is a randomized, open-label, two-arm, parallel-group, prospective interventional Phase III trial designed to evaluate the immunogenicity and safety of a quadrivalent human papillomavirus (HPV) vaccine when administered concomitantly with a tetanus-diphtheria (Td) vaccine in healthy children and adolescents aged 9 to 15 years.

Participants will be assigned to receive the quadrivalent HPV vaccine together with the Td vaccine or the quadrivalent HPV vaccine alone. The study will assess antibody responses to the HPV vaccine antigens. Safety will be evaluated throughout the study by monitoring solicited and unsolicited adverse events, serious adverse events, and other clinically relevant safety findings.

The study is intended to provide clinical evidence on the concomitant administration of the quadrivalent HPV vaccine with Td vaccine in the target pediatric population.

Inclusion criteria

• Age 9-15 years;
• Healthy;
• Subject/parent or LAR appropriately informed and consent/assent signed;
• Willing to comply with investigator instructions and study schedule.

Exclusion criteria

• Concurrent/other trial;
• Evolving illness/fever ≥37.5°C;
• Allergy to vaccine components;
• Uncontrolled coagulopathy/blood disorder contraindicating IM injection;
• Recent treatment likely to alter immune response; 6. Pregnancy/breastfeeding;

• Abnormality/chronic disease interfering with objectives; 8. History of HPV/diphtheria/tetanus infection; 9. Previous HPV vaccination.