inclusion criteria: * healthy children and adolescents aged 6 months to 17 years; * the participants and/or their guardians are able to understand and sign the informed consent voluntarily (in accordance with the local regulations); * able to comply with study procedures based on the assessment of the investigator; * female participants of childbearing potential (post-menarche girls or in accordance with the local standard of care) may be enrolled in the study if the participant fulfills all the following criteria: * has a negative pregnancy test on the day of the first dose (day 0). * has practiced adequate contraception or has abstained from all activities that could result in pregnancy for at least 28 days prior to the first dose (day 0). * has agreed to continue adequate contraception through 3 months following the second dose (day 28). * is not currently breastfeeding. * must be willing to provide verifiable identification (in accordance with the local regulations), has means to be contacted and to contact the investigator during the study.

inclusion criteria: * healthy children and adolescents aged 6 months to 17 years; * the participants and/or their guardians are able to understand and sign the informed consent voluntarily (in accordance with the local regulations); * able to comply with study procedures based on the assessment of the investigator; * female participants of childbearing potential (post-menarche girls or in accordance with the local standard of care) may be enrolled in the study if the participant fulfills all the following criteria: * has a negative pregnancy test on the day of the first dose (day 0). * has practiced adequate contraception or has abstained from all activities that could result in pregnancy for at least 28 days prior to the first dose (day 0). * has agreed to continue adequate contraception through 3 months following the second dose (day 28). * is not currently breastfeeding. * must be willing to provide verifiable identification (in accordance with the local regulations), has means to be contacted and to contact the investigator during the study.

inclusion criteria: - healthy children and adolescents aged 6 months to 17 years; - the participants and/or their guardians are able to understand and sign the informed consent voluntarily (in accordance with the local regulations); - able to comply with study procedures based on the assessment of the investigator; - female participants of childbearing potential (post-menarche girls or in accordance with the local standard of care) may be enrolled in the study if the participant fulfills all the following criteria: - has a negative pregnancy test on the day of the first dose (day 0). - has practiced adequate contraception or has abstained from all activities that could result in pregnancy for at least 28 days prior to the first dose (day 0). - has agreed to continue adequate contraception through 3 months following the second dose (day 28). - is not currently breastfeeding. - must be willing to provide verifiable identification (in accordance with the local regulations), has means to be contacted and to contact the investigator during the study.

inclusion criteria: - healthy children and adolescents aged 6 months to 17 years; - the participants and/or their guardians are able to understand and sign the informed consent voluntarily (in accordance with the local regulations); - able to comply with study procedures based on the assessment of the investigator; - female participants of childbearing potential (post-menarche girls or in accordance with the local standard of care) may be enrolled in the study if the participant fulfills all the following criteria: - has a negative pregnancy test on the day of the first dose (day 0). - has practiced adequate contraception or has abstained from all activities that could result in pregnancy for at least 28 days prior to the first dose (day 0). - has agreed to continue adequate contraception through 3 months following the second dose (day 28). - is not currently breastfeeding. - must be willing to provide verifiable identification (in accordance with the local regulations), has means to be contacted and to contact the investigator during the study.