HPV Vaccine Effectiveness in Partially Vaccinated Girls in Uganda
- Cervical cancer is one of the leading causes of cancer death in women worldwide and in Uganda. It is caused by the human papillomavirus (HPV). A vaccine against HPV was offered for all 10-year-old girls in the Nakasongola district of Uganda from October 1, 2008, to October 31, 2009. The HPV vaccine requires three doses; however, some girls received only one or two doses. Researchers want to compare vaccine immunogenicity in girls who received all three doses with those who had only one or two doses.
- To examine the immunogenicity (antibody levels) of girls in Uganda who received only one, two or three doses of HPV vaccine.
- Girls who will be at least 12 years old by October 31, 2011, and had at least one dose of the HPV vaccine.
- All participants will come from the Nakasongola district of Uganda.
- Participants will have a physical exam and answer questions about their medical history and HPV risk.
- Participants will provide a single blood sample for testing.
- Treatment and vaccines will not be provided as part of this study. Girls who did not receive all three doses of the HPV vaccine will be given information about the nearest health center. Health centers will provide the missed doses free of charge.
HPV16 Anitbody Levels Post Vaccination
HPV18 Antibody Levels Post Vaccination
|Study Design:||Time Perspective: Cross-Sectional|
|Official Title:||Immunogenicity of Bivalent HPV Vaccine Among Partially Vaccinated Young Adolescent Girls in Uganda|
- HPV Immunogenicity [ Time Frame: Ongoing ] [ Designated as safety issue: No ]
|Study Start Date:||January 2012|
Recent experience with HPV vaccine implementation in low resource settings has suggested that high vaccine coverage for all three doses could be achieved provided programs are planned well and have full and complementary components in place. However, some locations experienced substantial rates of partially vaccinated girls, those who received only one or two doses. From the vaccine trial data published thus far, we know that the vaccines produce high levels of type-specific anti-HPV antibodies which begin to stabilize past 24 months post-vaccination. Without an immune correlate of protection, it is difficult to know whether girls who received one or two vaccine doses will still experience the same benefit of protection from HPV infection as those who received all three doses of vaccine.
Recent data from a trial of a two-dose regimen of vaccination of girls aged 9-13 years in Vancouver, Canada have suggested that the immune response of girls who received only two doses was non-inferior both to that of girls who received 3 doses and to that of adult women aged 16-25 years who also received 3 doses. In a complementary study in Guanacaste, Costa Rica, vaccine efficacy (defined as 12-month vaccine type-specific infection persistence) among adult women who received either one or two doses of HPV vaccine as a part of the Phase IIb clinical trials of Cervarix (GSK) was similar to women who received all three vaccines doses.
This proposed study would provide additional insight into the immunogenicity of HPV vaccine among partially vaccinated girls in Uganda, which could add supportive evidence in an African adolescent population (currently not represented in any clinical studies of HPV vaccines) of the immunological implications of receiving less than 3 doses of HPV vaccine.
To investigate whether the anti-HPV 16 and/or anti-HPV-18 immune responses elicited by the bivalent vaccine for girls who received one dose and those who received two doses are similar at greater than or equal to 24 months (after last dose) to girls who received all three doses of bivalent HPV vaccine.
Girls who received at least one dose of the HPV vaccine, 12-20 years of old, in apparent good general health.
This is a cross-sectional immunogenicity study with three groups:
Group 1 - 200 girls who received only one dose of HPV vaccine as a part of the PATH-UNEPI HPV vaccine demonstration project;
Group 2 - 200 girls who received only two doses of HPV vaccine as a part of the PATH-UNEPI
HPV vaccine demonstration project; and
Group 3 - 200 girls who received all three doses of HPV vaccine as a part of the PATH-UNEPI HPV vaccine demonstration project.
This study will enroll girls (by group) within one district of Uganda from an HPV vaccine registry maintained by the district.
Antibody level will be parameterized as the geometric mean titre of serum antibody to HPV types 16 and/or 18 at greater than or equal to 24 months after last dose of vaccine. Titres will be measured using the polyclonal Direct VLP ELISA.
Please refer to this study by its ClinicalTrials.gov identifier: NCT01520272
|District of Nakasangola|
|Principal Investigator:||Allan Hildesheim, Ph.D.||National Cancer Institute (NCI)|