Participants with HPV 6/11/16/18-related external genital warts, penile/perianal/perineal intraepithelial neoplasia (PIN), penile, perianal or perineal cancer per 100 person-years of follow-up was assessed.

Participants must have received 3 doses of qHPV vaccine or placebo, have no protocol violations that could interfere with the effects of the vaccine, be seronegative at Day 1 and PCR negative Day 1 through Month 7 for the relevant HPV type, and must provide data after Month 7.

Incidence of HPV Type 6/11-related genital warts is expressed as events per 10,000 person-years of follow-up.

Participants must have received 3 doses of qHPV vaccine, have no protocol violations that could interfere with the effects of the vaccine, be seronegative at Day 1 and PCR negative Day 1 through Month 7 for the relevant HPV type, and must provide data after Month 7. This endpoint applied only to participants in the Base Study qHPV vaccine group.

Incidence of HPV Type 6/11/16/18-related external genital warts, PIN, penile, perianal or perineal cancer is expressed as events per 10,000 person-years of follow-up.

Participants must have received 3 doses of qHPV vaccine, have no protocol violations that could interfere with the effects of the vaccine, be seronegative at Day 1 and PCR negative Day 1 through Month 7 for the relevant HPV type, and must provide data after Month 7. This endpoint applied only to participants in the Base Study qHPV vaccine group.

Incidence of HPV Type 6/11/16/18-related AIN and anal cancer is expressed as events per 10,000 person-years of follow-up. MSM is men having sex with men.

Participants must have received 3 doses of qHPV vaccine, have no protocol violations that could interfere with the effects of the vaccine, be seronegative at Day 1 and PCR negative Day 1 through Month 7 for the relevant HPV type, and must provide data after Month 7. This endpoint applied only to MSM in the Base Study qHPV vaccine group.

An adverse event is defined as any unfavorable and unintended change in the structure, function, or chemistry of the body temporally associated with the use of the SPONSOR'S product, whether or not considered related to the use of the product. Any worsening of a preexisting condition which is temporally associated with the use of the SPONSOR'S product, is also an adverse experience. A severe AE is incapacitating with inability to work or do usual activities.

The analysis population included all vaccinated participants excluding 6 participants who received non-compliant mixed regimens of qHPV vaccine and placebo.

A serious adverse event is an AE that 1) results in death, 2) is life threatening, 3) results in persistent or significant disability or incapacity, 4) results in or prolongs an existing hospitalization, 5) is a congenital anomaly or birth defect, 6) is a cancer, 7) is an overdose, or 8) based on appropriate medical judgment may jeopardize the participant and may require medical or surgical intervention. A vaccine-related AE is one deemed to be possibly, probably or definitely related to study vaccine by the investigator.

The analysis population included all vaccinated participants excluding 6 participants who received non-compliant mixed regimens of qHPV vaccine and placebo.

An SAE is an AE that 1) results in death, 2) is life threatening, 3) results in persistent or significant disability or incapacity, 4) results in or prolongs an existing hospitalization, 5) is a congenital anomaly or birth defect, 6) is a cancer, 7) is an overdose, or 8) based on appropriate medical judgment may jeopardize the participant and may require medical or surgical intervention. A vaccine-related AE is one deemed to be possibly, probably or definitely related to study vaccine by the investigator.

The population analyzed was all randomized participants receiving at least 1 dose of qHPV vaccine in the Base Study or EXT1 and enrolled in LTFU (EXT2).

The number of participants who died was assessed.

The population analyzed was all randomized participants receiving at least 1 dose of qHPV vaccine in the Base Study or EXT1 and enrolled in LTFU (EXT2).

Participants with HPV 6/11/16/18-related AIN or anal cancer per 100 person-years of follow-up was assessed.

Only a subset of participants was included for this sub-study. Participants must have received 3 doses of qHPV vaccine or placebo, have no protocol violations that could interfere with the effects of the vaccine, be seronegative at Day 1 and PCR negative Day 1 through Month 7 for the relevant HPV type, and must provide data after Month 7.

Participants with HPV Type 6/11/16/18-related persistent infection per 100 person-years of follow-up was assessed.

Participants must have received 3 doses of qHPV vaccine or placebo, have no protocol violations that could interfere with the effects of the vaccine, be seronegative at Day 1 and PCR negative Day 1 through Month 7 for the relevant HPV type, and must provide data after Month 7.

Participants with HPV 6/11/16/18-related DNA detection per 100 person-years of follow-up was assessed.

Participants must have received 3 doses of qHPV vaccine or placebo, have no protocol violations that could interfere with the effects of the vaccine, be seronegative at Day 1 and PCR negative Day 1 through Month 7 for the relevant HPV type, and must provide data after Month 7.

Antibodies to HPV types were measured using cLIA. Antibody titers were expressed as cLIA milli Merck units/mL (cLIA mMU/mL).

All participants who 1) were seronegative at Day 1 and PCR negative Day 1 through Month 7 for the relevant HPV type, 2) received all 3 vaccinations, and 3) did not have protocol deviations that could interfere with the effects of the vaccine. Immunogenicity was assessed only for participants who received qHPV vaccine in the Base Study.

Antibodies to HPV types were measured using cLIA. Antibody titers were expressed as cLIA milli Merck units/mL (cLIA mMU/mL).

All participants who 1) were seronegative at Day 1 and PCR negative Day 1 through Month 7 for the relevant HPV type, 2) received all 3 vaccinations, and 3) did not have protocol deviations that could interfere with the effects of the vaccine. Immunogenicity was assessed only for participants who received qHPV vaccine in the Base Study.

Antibodies to HPV types were measured using cLIA. Antibody titers were expressed as cLIA milli Merck units/mL (cLIA mMU/mL).

All participants who 1) were seronegative at Day 1 and PCR negative Day 1 through Month 7 for the relevant HPV type, 2) received all 3 vaccinations, and 3) did not have protocol deviations that could interfere with the effects of the vaccine. Immunogenicity was assessed only for participants who received qHPV vaccine in the Base Study.

Antibodies to HPV types were measured using cLIA. Antibody titers were expressed as cLIA milli Merck units/mL (cLIA mMU/mL).

All participants who 1) were seronegative at Day 1 and PCR negative Day 1 through Month 7 for the relevant HPV type, 2) received all 3 vaccinations, and 3) did not have protocol deviations that could interfere with the effects of the vaccine. Immunogenicity was assessed only for participants who received qHPV vaccine in the Base Study.

Antibodies to HPV types were measured using cLIA. Thresholds for seropositive were ≥20, 16, 20, and 24 cLIA mMU/mL for HPV Types 6, 11, 16, and 18, respectively.

All participants who 1) were seronegative at Day 1 and PCR negative Day 1 through Month 7 for the relevant HPV type, 2) received all 3 vaccinations, and 3) did not have protocol deviations that could interfere with the effects of the vaccine. Immunogenicity was assessed only for participants who received qHPV vaccine in the Base Study.

Antibodies to HPV types were measured using cLIA. Thresholds for seropositive were ≥20, 16, 20, and 24 cLIA mMU/mL for HPV Types 6, 11, 16, and 18, respectively.

All participants who 1) were seronegative at Day 1 and PCR negative Day 1 through Month 7 for the relevant HPV type, 2) received all 3 vaccinations, and 3) did not have protocol deviations that could interfere with the effects of the vaccine. Immunogenicity was assessed only for participants who received qHPV vaccine in the Base Study.

Antibodies to HPV types were measured using cLIA. Thresholds for seropositive were ≥20, 16, 20, and 24 cLIA mMU/mL for HPV Types 6, 11, 16, and 18, respectively.

All participants who 1) were seronegative at Day 1 and PCR negative Day 1 through Month 7 for the relevant HPV type, 2) received all 3 vaccinations, and 3) did not have protocol deviations that could interfere with the effects of the vaccine. Immunogenicity was assessed only for participants who received qHPV vaccine in the Base Study.

Antibodies to HPV types were measured using cLIA. Thresholds for seropositive were ≥20, 16, 20, and 24 cLIA mMU/mL for HPV Types 6, 11, 16, and 18, respectively.

All participants who 1) were seronegative at Day 1 and PCR negative Day 1 through Month 7 for the relevant HPV type, 2) received all 3 vaccinations, and 3) did not have protocol deviations that could interfere with the effects of the vaccine. Immunogenicity was assessed only for participants who received qHPV vaccine in the Base Study.

Antibodies to HPV types were measured using Luminex immunoassay (IgG-LIA). The unit of measure for this assay is IgG LIA mMU/mL; this unit cannot be directly compared with the cLIA mMU/mL unit reported for the cLIA results.

All participants who 1) were seronegative at Day 1 and PCR negative Day 1 through Month 7 for the relevant HPV type, 2) received all 3 vaccinations, and 3) did not have protocol deviations that could interfere with the effects of the vaccine. Immunogenicity was assessed only for participants who received qHPV vaccine in the Base Study.

Antibodies to HPV types were measured using IgG LIA. Thresholds for seropositive were ≥9, 6, 5, and 5 IgG LIA mMU/mL for HPV Types 6, 11, 16, and 18, respectively.

All participants who 1) were seronegative at Day 1 and PCR negative Day 1 through Month 7 for the relevant HPV type, 2) received all 3 vaccinations, and 3) did not have protocol deviations that could interfere with the effects of the vaccine. Immunogenicity was assessed only for participants who received qHPV vaccine in the Base Study..