inclusion criteria: subjects must meet all of the following inclusion criteria at the screening (visit 1) and/or vaccination (visit 2) visits to be eligible for participation in this study; no protocol waivers are allowed. all investigator assessment-based judgements must be carefully and fully documented in the source documents: 1. subjects must have read, understood, and signed the informed consent form (icf) prior to participating in the study; subjects must also complete study-related procedures and communicate with the study staff at visits and by phone during the study; 2. at the screening visit (visit 1), male and female subjects must be 18 to 55 (has not yet had his/her 56th birthday) years of age, inclusive; 3. at screening (visit 1) and vaccination (visit 2), subject must have a body mass index (bmi) of ≥ 18.5 and \< 25 kg/m2; 4. subjects are considered by the investigator to be reliable and likely to cooperate with the assessment procedures and be available for the duration of the study; 5. subjects must be healthy (no clinically significant health concerns) as determined by medical history, physical examination, vital signs, and clinical laboratory tests. investigator discretion will be permitted with this inclusion criterion; 6. female subjects of childbearing potential must have a negative serum pregnancy test result at screening (visit 1) and a negative urine pregnancy test result at vaccination (visit 2 and visit 4). non-childbearing females are defined as: * surgically-sterile (defined as bilateral tubal ligation, hysterectomy or bilateral oophorectomy performed more than one month prior to the first study vaccination); or * post-menopausal (absence of menses for 12 consecutive months and age consistent with natural cessation of ovulation); 7. female subjects of childbearing potential must use an effective method of contraception for one month prior to vaccination (visit 2) and agree to continue employing highly effective birth control measures for at least one month after the last administration of the investigational product (or in the case of early termination, she must not plan to become pregnant for at least one month after her last study vaccination). the following relationship or methods of contraception are considered to be highly effective: * combined (estrogen and progestogen containing) hormonal contraception associated with inhibition of ovulation: * oral; * intravaginal; * transdermal; * progestogen-only hormonal contraception associated with inhibition of ovulation: * oral; * injectable; * implantable; * intra-uterine device with or without hormonal release; * vasectomised partner, provided that this partner is the sole sexual partner of the study participant and that the vasectomised partner has received a medical assessment of the surgical success; * credible self-reported history of heterosexual vaginal intercourse abstinence prior to and for at least one month after the last administration of the investigational product ; * female partner.

inclusion criteria: subjects must meet all of the following inclusion criteria at the screening (visit 1) and/or vaccination (visit 2) visits to be eligible for participation in this study; no protocol waivers are allowed. all investigator assessment-based judgements must be carefully and fully documented in the source documents: 1. subjects must have read, understood, and signed the informed consent form (icf) prior to participating in the study; subjects must also complete study-related procedures and communicate with the study staff at visits and by phone during the study; 2. at the screening visit (visit 1), male and female subjects must be 18 to 55 (has not yet had his/her 56th birthday) years of age, inclusive; 3. at screening (visit 1) and vaccination (visit 2), subject must have a body mass index (bmi) of ≥ 18.5 and \< 25 kg/m2; 4. subjects are considered by the investigator to be reliable and likely to cooperate with the assessment procedures and be available for the duration of the study; 5. subjects must be healthy (no clinically significant health concerns) as determined by medical history, physical examination, vital signs, and clinical laboratory tests. investigator discretion will be permitted with this inclusion criterion; 6. female subjects of childbearing potential must have a negative serum pregnancy test result at screening (visit 1) and a negative urine pregnancy test result at vaccination (visit 2 and visit 4). non-childbearing females are defined as: * surgically-sterile (defined as bilateral tubal ligation, hysterectomy or bilateral oophorectomy performed more than one month prior to the first study vaccination); or * post-menopausal (absence of menses for 12 consecutive months and age consistent with natural cessation of ovulation); 7. female subjects of childbearing potential must use an effective method of contraception for one month prior to vaccination (visit 2) and agree to continue employing highly effective birth control measures for at least one month after the last administration of the investigational product (or in the case of early termination, she must not plan to become pregnant for at least one month after her last study vaccination). the following relationship or methods of contraception are considered to be highly effective: * combined (estrogen and progestogen containing) hormonal contraception associated with inhibition of ovulation: * oral; * intravaginal; * transdermal; * progestogen-only hormonal contraception associated with inhibition of ovulation: * oral; * injectable; * implantable; * intra-uterine device with or without hormonal release; * vasectomised partner, provided that this partner is the sole sexual partner of the study participant and that the vasectomised partner has received a medical assessment of the surgical success; * credible self-reported history of heterosexual vaginal intercourse abstinence prior to and for at least one month after the last administration of the investigational product ; * female partner.

inclusion criteria: subjects must meet all of the following inclusion criteria at the screening (visit 1) and/or vaccination (visit 2) visits to be eligible for participation in this study; no protocol waivers are allowed. all investigator assessment-based judgements must be carefully and fully documented in the source documents: subjects must have read, understood, and signed the informed consent form (icf) prior to participating in the study; subjects must also complete study-related procedures and communicate with the study staff at visits and by phone during the study; at the screening visit (visit 1), male and female subjects must be 18 to 55 (has not yet had his/her 56th birthday) years of age, inclusive; at screening (visit 1) and vaccination (visit 2), subject must have a body mass index (bmi) of ≥ 18.5 and < 25 kg/m2; subjects are considered by the investigator to be reliable and likely to cooperate with the assessment procedures and be available for the duration of the study; subjects must be healthy (no clinically significant health concerns) as determined by medical history, physical examination, vital signs, and clinical laboratory tests. investigator discretion will be permitted with this inclusion criterion; female subjects of childbearing potential must have a negative serum pregnancy test result at screening (visit 1) and a negative urine pregnancy test result at vaccination (visit 2 and visit 4). non-childbearing females are defined as: surgically-sterile (defined as bilateral tubal ligation, hysterectomy or bilateral oophorectomy performed more than one month prior to the first study vaccination); or post-menopausal (absence of menses for 12 consecutive months and age consistent with natural cessation of ovulation); female subjects of childbearing potential must use an effective method of contraception for one month prior to vaccination (visit 2) and agree to continue employing highly effective birth control measures for at least one month after the last administration of the investigational product (or in the case of early termination, she must not plan to become pregnant for at least one month after her last study vaccination). the following relationship or methods of contraception are considered to be highly effective: combined (estrogen and progestogen containing) hormonal contraception associated with inhibition of ovulation: oral; intravaginal; transdermal; progestogen-only hormonal contraception associated with inhibition of ovulation: oral; injectable; implantable; intra-uterine device with or without hormonal release; vasectomised partner, provided that this partner is the sole sexual partner of the study participant and that the vasectomised partner has received a medical assessment of the surgical success; credible self-reported history of heterosexual vaginal intercourse abstinence prior to and for at least one month after the last administration of the investigational product ; female partner.

inclusion criteria: subjects must meet all of the following inclusion criteria at the screening (visit 1) and/or vaccination (visit 2) visits to be eligible for participation in this study; no protocol waivers are allowed. all investigator assessment-based judgements must be carefully and fully documented in the source documents: subjects must have read, understood, and signed the informed consent form (icf) prior to participating in the study; subjects must also complete study-related procedures and communicate with the study staff at visits and by phone during the study; at the screening visit (visit 1), male and female subjects must be 18 to 55 (has not yet had his/her 56th birthday) years of age, inclusive; at screening (visit 1) and vaccination (visit 2), subject must have a body mass index (bmi) of ≥ 18.5 and < 25 kg/m2; subjects are considered by the investigator to be reliable and likely to cooperate with the assessment procedures and be available for the duration of the study; subjects must be healthy (no clinically significant health concerns) as determined by medical history, physical examination, vital signs, and clinical laboratory tests. investigator discretion will be permitted with this inclusion criterion; female subjects of childbearing potential must have a negative serum pregnancy test result at screening (visit 1) and a negative urine pregnancy test result at vaccination (visit 2 and visit 4). non-childbearing females are defined as: surgically-sterile (defined as bilateral tubal ligation, hysterectomy or bilateral oophorectomy performed more than one month prior to the first study vaccination); or post-menopausal (absence of menses for 12 consecutive months and age consistent with natural cessation of ovulation); female subjects of childbearing potential must use an effective method of contraception for one month prior to vaccination (visit 2) and agree to continue employing highly effective birth control measures for at least one month after the last administration of the investigational product (or in the case of early termination, she must not plan to become pregnant for at least one month after her last study vaccination). the following relationship or methods of contraception are considered to be highly effective: combined (estrogen and progestogen containing) hormonal contraception associated with inhibition of ovulation: oral; intravaginal; transdermal; progestogen-only hormonal contraception associated with inhibition of ovulation: oral; injectable; implantable; intra-uterine device with or without hormonal release; vasectomised partner, provided that this partner is the sole sexual partner of the study participant and that the vasectomised partner has received a medical assessment of the surgical success; credible self-reported history of heterosexual vaginal intercourse abstinence prior to and for at least one month after the last administration of the investigational product ; female partner.

inclusion criteria: subjects must meet all of the following inclusion criteria at the screening (visit 1) and/or vaccination (visit 2) visits to be eligible for participation in this study; no protocol waivers are allowed. all investigator assessment-based judgements must be carefully and fully documented in the source documents: 1. subjects must have read, understood, and signed the informed consent form (icf) prior to participating in the study; subjects must also complete study-related procedures and communicate with the study staff at visits and by phone during the study; 2. at the screening visit (visit 1), male and female subjects must be 18 to 55 (has not yet had his/her 56th birthday) years of age, inclusive; 3. at screening (visit 1) and vaccination (visit 2), subject must have a body mass index (bmi) of ≥ 18.5 and < 25 kg/m2; 4. subjects are considered by the investigator to be reliable and likely to cooperate with the assessment procedures and be available for the duration of the study; 5. subjects must be healthy (no clinically significant health concerns) as determined by medical history, physical examination, vital signs, and clinical laboratory tests. investigator discretion will be permitted with this inclusion criterion; 6. female subjects of childbearing potential must have a negative serum pregnancy test result at screening (visit 1) and a negative urine pregnancy test result at vaccination (visit 2 and visit 4). non-childbearing females are defined as: - surgically-sterile (defined as bilateral tubal ligation, hysterectomy or bilateral oophorectomy performed more than one month prior to the first study vaccination); or - post-menopausal (absence of menses for 12 consecutive months and age consistent with natural cessation of ovulation); 7. female subjects of childbearing potential must use an effective method of contraception for one month prior to vaccination (visit 2) and agree to continue employing highly effective birth control measures for at least one month after the last administration of the investigational product (or in the case of early termination, she must not plan to become pregnant for at least one month after her last study vaccination). the following relationship or methods of contraception are considered to be highly effective: - combined (estrogen and progestogen containing) hormonal contraception associated with inhibition of ovulation: - oral; - intravaginal; - transdermal; - progestogen-only hormonal contraception associated with inhibition of ovulation: - oral; - injectable; - implantable; - intra-uterine device with or without hormonal release; - vasectomised partner, provided that this partner is the sole sexual partner of the study participant and that the vasectomised partner has received a medical assessment of the surgical success; - credible self-reported history of heterosexual vaginal intercourse abstinence prior to and for at least one month after the last administration of the investigational product ; - female partner.

inclusion criteria: subjects must meet all of the following inclusion criteria at the screening (visit 1) and/or vaccination (visit 2) visits to be eligible for participation in this study; no protocol waivers are allowed. all investigator assessment-based judgements must be carefully and fully documented in the source documents: 1. subjects must have read, understood, and signed the informed consent form (icf) prior to participating in the study; subjects must also complete study-related procedures and communicate with the study staff at visits and by phone during the study; 2. at the screening visit (visit 1), male and female subjects must be 18 to 55 (has not yet had his/her 56th birthday) years of age, inclusive; 3. at screening (visit 1) and vaccination (visit 2), subject must have a body mass index (bmi) of ≥ 18.5 and < 25 kg/m2; 4. subjects are considered by the investigator to be reliable and likely to cooperate with the assessment procedures and be available for the duration of the study; 5. subjects must be healthy (no clinically significant health concerns) as determined by medical history, physical examination, vital signs, and clinical laboratory tests. investigator discretion will be permitted with this inclusion criterion; 6. female subjects of childbearing potential must have a negative serum pregnancy test result at screening (visit 1) and a negative urine pregnancy test result at vaccination (visit 2 and visit 4). non-childbearing females are defined as: - surgically-sterile (defined as bilateral tubal ligation, hysterectomy or bilateral oophorectomy performed more than one month prior to the first study vaccination); or - post-menopausal (absence of menses for 12 consecutive months and age consistent with natural cessation of ovulation); 7. female subjects of childbearing potential must use an effective method of contraception for one month prior to vaccination (visit 2) and agree to continue employing highly effective birth control measures for at least one month after the last administration of the investigational product (or in the case of early termination, she must not plan to become pregnant for at least one month after her last study vaccination). the following relationship or methods of contraception are considered to be highly effective: - combined (estrogen and progestogen containing) hormonal contraception associated with inhibition of ovulation: - oral; - intravaginal; - transdermal; - progestogen-only hormonal contraception associated with inhibition of ovulation: - oral; - injectable; - implantable; - intra-uterine device with or without hormonal release; - vasectomised partner, provided that this partner is the sole sexual partner of the study participant and that the vasectomised partner has received a medical assessment of the surgical success; - credible self-reported history of heterosexual vaginal intercourse abstinence prior to and for at least one month after the last administration of the investigational product ; - female partner.