inclusion criteria: 1. written informed consent by the participant's legal representative(s), according to local requirements, and written informed assent of the participant, if applicable, prior to any study related procedures. 2. participants of either gender aged between 2 years and \<12 years at screening. 3. regarding history of menactra (meningococcal vaccination): only participants \<5 years can be included who received no menactra vaccination. participants ≥5 years can be included, if at least 4 years have elapsed since the prior dose. 4. medically stable such that, according to the judgment of the investigator the participant appears likely to be able to remain on study through the end of protocol-specified follow-up. • for participants with chronic diseases (such as, asthma, diabetes mellitus, cystic fibrosis, human immunodeficiency virus \[hiv\] infection), the disease should be stable, defined as not requiring significant change in therapy or hospitalization for worsening disease during the 3 months prior to the expected day of randomization (visit 1) and as per investigator assessment. 5. must be able to attend all visits of the study and comply with all study procedures, including daily completion of the e-diary after each vaccination. 6. female participants of non-childbearing potential may be enrolled. for this study, non-childbearing potential is defined as pre-menarche. 7. female participants of childbearing potential (wocbp) might be enrolled if: * have a negative pregnancy test on the day of vaccination, * have practiced adequate contraception\* or has abstained from all activities that could result in pregnancy for at least 28 days prior to the first injection, * have agreed to continue adequate contraception or abstinence through 3 months following the second injection (phase 2 part) or following the third vaccination (phase 3 part), * are not currently breastfeeding.

inclusion criteria: 1. written informed consent by the participant's legal representative(s), according to local requirements, and written informed assent of the participant, if applicable, prior to any study related procedures. 2. participants of either gender aged between 2 years and \<12 years at screening. 3. regarding history of menactra (meningococcal vaccination): only participants \<5 years can be included who received no menactra vaccination. participants ≥5 years can be included, if at least 4 years have elapsed since the prior dose. 4. medically stable such that, according to the judgment of the investigator the participant appears likely to be able to remain on study through the end of protocol-specified follow-up. • for participants with chronic diseases (such as, asthma, diabetes mellitus, cystic fibrosis, human immunodeficiency virus \[hiv\] infection), the disease should be stable, defined as not requiring significant change in therapy or hospitalization for worsening disease during the 3 months prior to the expected day of randomization (visit 1) and as per investigator assessment. 5. must be able to attend all visits of the study and comply with all study procedures, including daily completion of the e-diary after each vaccination. 6. female participants of non-childbearing potential may be enrolled. for this study, non-childbearing potential is defined as pre-menarche. 7. female participants of childbearing potential (wocbp) might be enrolled if: * have a negative pregnancy test on the day of vaccination, * have practiced adequate contraception\* or has abstained from all activities that could result in pregnancy for at least 28 days prior to the first injection, * have agreed to continue adequate contraception or abstinence through 3 months following the second injection (phase 2 part) or following the third vaccination (phase 3 part), * are not currently breastfeeding.

inclusion criteria: written informed consent by the participant's legal representative(s), according to local requirements, and written informed assent of the participant, if applicable, prior to any study related procedures. participants of either gender aged between 2 years and <12 years at screening. regarding history of menactra (meningococcal vaccination): only participants <5 years can be included who received no menactra vaccination. participants ≥5 years can be included, if at least 4 years have elapsed since the prior dose. medically stable such that, according to the judgment of the investigator the participant appears likely to be able to remain on study through the end of protocol-specified follow-up. • for participants with chronic diseases (such as, asthma, diabetes mellitus, cystic fibrosis, human immunodeficiency virus [hiv] infection), the disease should be stable, defined as not requiring significant change in therapy or hospitalization for worsening disease during the 3 months prior to the expected day of randomization (visit 1) and as per investigator assessment. must be able to attend all visits of the study and comply with all study procedures, including daily completion of the e-diary after each vaccination. female participants of non-childbearing potential may be enrolled. for this study, non-childbearing potential is defined as pre-menarche. female participants of childbearing potential (wocbp) might be enrolled if: have a negative pregnancy test on the day of vaccination, have practiced adequate contraception* or has abstained from all activities that could result in pregnancy for at least 28 days prior to the first injection, have agreed to continue adequate contraception or abstinence through 3 months following the second injection (phase 2 part) or following the third vaccination (phase 3 part), are not currently breastfeeding.

inclusion criteria: written informed consent by the participant's legal representative(s), according to local requirements, and written informed assent of the participant, if applicable, prior to any study related procedures. participants of either gender aged between 2 years and <12 years at screening. regarding history of menactra (meningococcal vaccination): only participants <5 years can be included who received no menactra vaccination. participants ≥5 years can be included, if at least 4 years have elapsed since the prior dose. medically stable such that, according to the judgment of the investigator the participant appears likely to be able to remain on study through the end of protocol-specified follow-up. • for participants with chronic diseases (such as, asthma, diabetes mellitus, cystic fibrosis, human immunodeficiency virus [hiv] infection), the disease should be stable, defined as not requiring significant change in therapy or hospitalization for worsening disease during the 3 months prior to the expected day of randomization (visit 1) and as per investigator assessment. must be able to attend all visits of the study and comply with all study procedures, including daily completion of the e-diary after each vaccination. female participants of non-childbearing potential may be enrolled. for this study, non-childbearing potential is defined as pre-menarche. female participants of childbearing potential (wocbp) might be enrolled if: have a negative pregnancy test on the day of vaccination, have practiced adequate contraception* or has abstained from all activities that could result in pregnancy for at least 28 days prior to the first injection, have agreed to continue adequate contraception or abstinence through 3 months following the second injection (phase 2 part) or following the third vaccination (phase 3 part), are not currently breastfeeding.

inclusion criteria: written informed consent by the participant's legal representative(s), according to local requirements, and written informed assent of the participant, if applicable, prior to any study related procedures. participants of either gender aged between 2 years and <12 years at screening. regarding history of menactra (meningococcol vaccination): only participants <5 years can be included who received no menactra vaccination. participants ≥5 years can be included, if at least 4 years have elapsed since the prior dose. medically stable such that, according to the judgment of the investigator the participant appears likely to be able to remain on study through the end of protocol-specified follow-up. • for participants with chronic diseases (such as, asthma, diabetes mellitus, cystic fibrosis, human immunodeficiency virus [hiv] infection), the disease should be stable, defined as not requiring significant change in therapy or hospitalization for worsening disease during the 3 months prior to the expected day of randomization (visit 1) and as per investigator assessment. must be able to attend all visits of the study and comply with all study procedures, including daily completion of the e-diary after each vaccination. female participants of non-childbearing potential may be enrolled. for this study, non-childbearing potential is defined as pre-menarche. female participants of childbearing potential (wocbp) might be enrolled if: have a negative pregnancy test on the day of vaccination, have practiced adequate contraception* or has abstained from all activities that could result in pregnancy for at least 28 days prior to the first injection, have agreed to continue adequate contraception or abstinence through 3 months following the second injection (phase 2 part) or following the third vaccination (phase 3 part), are not currently breastfeeding.

inclusion criteria: written informed consent by the participant's legal representative(s), according to local requirements, and written informed assent of the participant, if applicable, prior to any study related procedures. participants of either gender aged between 2 years and <12 years at screening. regarding history of menactra (meningococcol vaccination): only participants <5 years can be included who received no menactra vaccination. participants ≥5 years can be included, if at least 4 years have elapsed since the prior dose. medically stable such that, according to the judgment of the investigator the participant appears likely to be able to remain on study through the end of protocol-specified follow-up. • for participants with chronic diseases (such as, asthma, diabetes mellitus, cystic fibrosis, human immunodeficiency virus [hiv] infection), the disease should be stable, defined as not requiring significant change in therapy or hospitalization for worsening disease during the 3 months prior to the expected day of randomization (visit 1) and as per investigator assessment. must be able to attend all visits of the study and comply with all study procedures, including daily completion of the e-diary after each vaccination. female participants of non-childbearing potential may be enrolled. for this study, non-childbearing potential is defined as pre-menarche. female participants of childbearing potential (wocbp) might be enrolled if: have a negative pregnancy test on the day of vaccination, have practiced adequate contraception* or has abstained from all activities that could result in pregnancy for at least 28 days prior to the first injection, have agreed to continue adequate contraception or abstinence through 3 months following the second injection (phase 2 part) or following the third vaccination (phase 3 part), are not currently breastfeeding.