Placebo (normal saline (0.9% NaCl) IM injection.

Solicited local AEs (at injection site) included pain/tenderness (mild: mild discomfort to touch, moderate: discomfort with movement, severe: significant discomfort at rest, potentially life-threatening: ER visit or hospitalization), erythema/redness (mild: 2.5 - 5 cm, moderate: 5.1 - 10 cm, severe: > 10 cm, potentially life-threatening: necrosis or exfoliative dermatitis), and swelling/induration (mild: 2.5 - 5 cm and does not interfere with activity, moderate: 5.1 - 10 cm or interferes with activity, severe: > 10 cm or prevents daily activity, potentially life-threatening: Necrosis). Data will be reported for the overall study population and in FV naïve participants only.

Solicited systemic AEs included fever, headache, fatigue, malaise, arthralgia, and myalgia that occurred within 7 days of first vaccination. Solicited systemic AEs will be graded from 1(mild) to 4(potentially life threatening) by severity. Fever: Grade 1(mild)= 38.0-38.4 degrees Celsius(°C)/100.4-101.1 degrees Fahrenheit (°F), Grade 2(moderate)=38.5-38.9°C/101.2-102.0°F, Grade 3(severe)=39.0-40°C/102.1-104°F, Grade 4 (potentially life threatening)=>40°C/>104°F. Headache, fatigue, malaise, arthralgia, and myalgia: Grade 1=no interference with activity, Grade 2=some interference with activity(Headache: repeated use of non-narcotic pain reliever>24 hours or some interference with activity), Grade 3 =significant; prevents daily activity(Headache: significant; any use of narcotic pain reliever or prevents daily activity), and Grade 4=ER visit or hospitalization. Data will be reported for the overall study population and in FV naïve participants only.

Solicited systemic AEs included fever, headache, fatigue, malaise, arthralgia, and myalgia that occurred within 7 days of first vaccination. Solicited systemic AEs will be graded from 1(mild) to 4(potentially life threatening) by severity. Fever: Grade 1(mild)= 38.0-38.4°C/100.4-101.1°F, Grade 2(moderate)=38.5-38.9°C/101.2-102.0°F, Grade 3(severe)=39.0-40°C/102.1-104°F, Grade 4 (potentially life threatening)=>40°C/>104°F. Headache, fatigue, malaise, arthralgia, and myalgia: Grade 1=no interference with activity, Grade 2=some interference with activity(Headache: repeated use of non-narcotic pain reliever>24 hours or some interference with activity), Grade 3 =significant; prevents daily activity(Headache: significant; any use of narcotic pain reliever or prevents daily activity), and Grade 4=ER visit or hospitalization. Data will be reported for the overall study population and in FV naïve participants only.

An unsolicited AE is any AE reported by the participant that is either not specified as a solicited AE or is specified as a solicited AE but starts outside the period for reporting solicited AE (ie, 7 days in total including the day of PIZV or placebo administration). Unsolicited AEs will be graded from 1 to 4 by severity, where Grade 1 (mild)= no interference with activity, Grade 2 (moderate)= some interference with activity, Grade 3 (severe)= significant; prevents daily activity, and Grade 4 (potentially life threatening)= ER visit or hospitalization. Data will be reported for the overall study population and in FV naïve participants only.

An unsolicited AE is any AE reported by the participant that is either not specified as a solicited AE or is specified as a solicited AE but starts outside the period for reporting solicited AE (ie, 7 days in total including the day of PIZV or placebo administration). Unsolicited AEs will be graded from 1 to 4 by severity, where Grade 1 (mild)= no interference with activity, Grade 2 (moderate)= some interference with activity, Grade 3 (severe)= significant; prevents daily activity, and Grade 4 (potentially life threatening)= ER visit or hospitalization. Data will be reported for the overall study population and in FV naïve participants only.

An SAE will be defined as any untoward medical occurrence that: 1) results in death, 2) is life-threatening, 3) requires inpatient hospitalization or prolongation of existing hospitalization, 4) results in persistent or significant disability/incapacity, 5) leads to a congenital anomaly/birth defect in the offspring of the participant or 6) is an important medical event that satisfies any of the following: a) May require intervention to prevent items 1 through 5 above. b) May expose the participant to danger, even though the event is not immediately life threatening or fatal or does not result in hospitalization. Data will be reported for the overall study population and in FV naïve participants only.

An AE is defined as any untoward medical occurrence in a clinical investigation participant administered an PIZV or placebo; it does not necessarily have to have a causal relationship with PIZV or placebo administration. AESI is defined as an AE collected through the study period and entered in the eCRF by the investigator or designee within 24 hours of becoming aware of the event which includes new onset of or worsening of the following neurologic diseases: Guillain-Barré syndrome (GBS), acute disseminated encephalomyelitis, idiopathic peripheral facial nerve palsy (Bell's palsy), seizures including but not limited to febrile seizures and/or generalized seizures/convulsions, and anaphylaxis. Data will be reported for the overall study population and in FV naïve participants only.

AE: any untoward medical occurrence in a clinical investigation participant administered PIZV or placebo; it does not necessarily have to have a causal relationship with trial vaccine administration. MAAEs is defined as AEs leading to an unscheduled visit to or by a healthcare professional including visits to an emergency department, but not fulfilling seriousness criteria. Data will be reported for the overall study population and in FV naïve participants only.

Seropositive participants are defined as participants with quantifiable (tested positive at or above the LOQ) serum neutralizing anti-ZIKV antibodies. Data will be reported for FV exposed participants only.

Seroconversion is defined as the percentage of participants with either pre-vaccination titer \

Seroconversion is defined as the percentage of participants with either pre-vaccination titer \

GMTs for neutralizing antibodies against ZIKV will be measured by assessing the quantity of neutralizing antibodies that bind ZIKV. Data will be reported for the overall study population and in FV naïve participants only.

GMTs for neutralizing antibodies against ZIKV will be measured by assessing the quantity of neutralizing antibodies that bind ZIKV. Data will be reported for FV exposed participants only.

An SAE will be defined as any untoward medical occurrence that: 1) results in death, 2) is life-threatening, 3) requires inpatient hospitalization or prolongation of existing hospitalization, 4) results in persistent or significant disability/incapacity, 5) leads to a congenital anomaly/birth defect in the offspring of the participant or 6) is an important medical event that satisfies any of the following: a) May require intervention to prevent items 1 through 5 above. b) May expose the participant to danger, even though the event is not immediately life threatening or fatal or does not result in hospitalization. Data will be reported for the overall study population and in FV naïve participants only.

An SAE will be defined as any untoward medical occurrence that: 1) results in death, 2) is life-threatening, 3) requires inpatient hospitalization or prolongation of existing hospitalization, 4) results in persistent or significant disability/incapacity, 5) leads to a congenital anomaly/birth defect in the offspring of the participant or 6) is an important medical event that satisfies any of the following: a) May require intervention to prevent items 1 through 5 above. b) May expose the participant to danger, even though the event is not immediately life threatening or fatal or does not result in hospitalization. Data will be reported for FV exposed participants only.

AE: any untoward medical occurrence in a clinical investigation participant administered PIZV or placebo; it does not necessarily have to have a causal relationship with trial vaccine administration. An AE will be considered AESI if any participant experiences a new onset of or worsening of the following neurologic diseases: GBS, acute disseminated encephalomyelitis, idiopathic peripheral facial nerve palsy (Bell's palsy), seizures including but not limited to febrile seizures and/or generalized seizures/convulsions and/or anaphylaxis. Data will be reported for the overall study population and in FV naïve participants only.

AE: any untoward medical occurrence in a clinical investigation participant administered PIZV or placebo; it does not necessarily have to have a causal relationship with trial vaccine administration. An AE will be considered AESI if any participant experiences a new onset of or worsening of the following neurologic diseases: GBS, acute disseminated encephalomyelitis, idiopathic peripheral facial nerve palsy (Bell's palsy), seizures including but not limited to febrile seizures and/or generalized seizures/convulsions and/or anaphylaxis. Data will be reported for FV exposed participants only.

AE: any untoward medical occurrence in a clinical investigation participant administered PIZV or placebo; it does not necessarily have to have a causal relationship with trial vaccine administration. MAAEs is defined as AEs leading to an unscheduled visit to or by a healthcare professional including visits to an emergency department, but not fulfilling seriousness criteria. Data will be reported for the overall study population and in FV naïve participants only.

AE: any untoward medical occurrence in a clinical investigation participant administered PIZV or placebo; it does not necessarily have to have a causal relationship with trial vaccine administration. MAAEs is defined as AEs leading to an unscheduled visit to or by a healthcare professional including visits to an emergency department, but not fulfilling seriousness criteria. Data will be reported for FV exposed participants only.