• Known exposure to Shigella during lifetime of the participant as confirmed during interview with the participant or documented by patient records (e.g., history of microbiologically-confirmed Shigella infection), recent travel* (within 2 years) to a country where Shigella or other enteric infections are endemic, or recent occupation* (within 3 years) involving Shigella species.

  *Exclusion due to travel or occupation is applicable only to Adults 18 to 50 years of age in Europe (Stage 1).

• Progressive, unstable or uncontrolled clinical conditions.

• History (known or suspected) of any reaction or hypersensitivity likely to be exacerbated by any component of the study vaccine.

• Any confirmed or suspected immunosuppressive or immunodeficient condition, based on medical history and physical examination (no laboratory testing required).

• Hypersensitivity, including allergy, to medicinal products or medical equipment whose use is foreseen in this study.

• Clinical conditions representing a contraindication to IM vaccination and blood draws.

• Any behavioural or cognitive impairment or psychiatric disease that, in the opinion of the investigator, may interfere with the participant's ability to participate in the study.

• Acute disease and/or fever (defined as temperature ≥38.0°C) at the time of enrolment*.

  • The participant can still be enrolled into the study at a time when the acute disease and/or fever has resolved.

• Any clinically significant haematological and/or biochemical laboratory abnormality.

• Confirmed positive COVID-19 test during the period starting 30 days before the first administration of study vaccines (Day -30 to Day 1).

• Any other clinical condition that, in the opinion of the investigator, might pose additional risk to the participant due to participation in the study.

• Administration of long-acting immune-modifying drugs at any time during the study period (e.g. infliximab).

• Prior receipt of an experimental Shigella vaccine or live Shigella challenge.

• Use of any investigational or non-registered product (drug, vaccine or medical device)* other than the study vaccine during the period starting 30 days before the first dose of study intervention (Day -30 to Day 1), or planned use during the study period.

  *Use of herbs and traditional treatments is not considered an exclusion criterion

• A vaccine not foreseen* by the Study Protocol administered during the period starting at -21 days before the first dose (-28 days in the case of live vaccines) and ending after the last dose of study intervention administration**.

  *Vaccines allowed by the Protocol include flu and COVID-19 vaccines in all participants and EPI vaccines in children and infants.

  **In case of emergency mass vaccination, the time period above can be reduced.

• Concurrently participating in another clinical study, at any time during the study period, in which the participant has been or will be exposed to an investigational or a non-investigational intervention (drug or invasive medical device).

• Any study personnel or immediate dependents, family, or household member.

Adults 18 to 50 years of age:

• Acute or chronic illness, clinically significant pulmonary, cardiovascular, hepatic or renal functional abnormality, as determined by physical examination or laboratory screening tests.
• Chronic administration (defined as more than 14 days in total) of immunosuppressants or other immune-modifying drugs during the period starting 3 months prior to the first vaccine study intervention. For corticosteroids, this will mean prednisone equivalent ≥20 mg/day for adult participants. Inhaled and topical steroids are allowed.
• Pregnant or lactating female.
• Female planning to become pregnant or planning to discontinue contraceptive precautions.
• History of or current chronic alcohol consumption and/or drug abuse.

Adults 18 to 50 years of age and Children 24 to 59 months age:

• Administration of immunoglobulins and/or any blood products or plasma derivatives, or bone marrow transplantation, during the period starting 3 months before the first dose of study vaccine or planned administration during the study period.

Children 24 to 59 months of age and infants 9 months of age:

• Acute or chronic clinically significant pulmonary, cardiovascular, hepatic or renal functional abnormality, as determined by physical examination or laboratory screening tests.
• Chronic administration (defined as more than 14 days in total) of immunosuppressants or other immune-modifying drugs during the period starting 3 months prior to the first vaccine dose. For corticosteroids, this will mean prednisone ≥0.5 mg/kg/day or 20 mg/day whichever is the maximum dose for paediatric participants. Inhaled and topical steroids are allowed.
• Child in care.

Infants 9 months of age:

• Administration of immunoglobulins and/or any blood products or plasma derivatives, or bone marrow transplantation, from birth or planned administration during the study period.