A Study on the Safety and Immune Responses to the GVGH altSonflex1-2-3 Vaccine Against Shigellosis in Adults, Children, and Infants

Inclusion Criteria:

All participants:

• Participants and/or participants' parent(s)/legally acceptable representative(s)LAR(s), who, in the opinion of the investigator, can and will comply with therequirements of the protocol (e.g. completion of the diary cards, return forfollow-up visits).

• Written or witnessed/thumb printed informed consent obtained from theparticipant/parent(s)/LAR(s) of the participant prior to performance of any studyspecific procedure.

• Healthy participants as established by medical history, clinical examination, andlaboratory assessment.

• Participants satisfying all screening requirements.

• Participants seronegative for hepatitis B, and hepatitis C.

• Participants negative for human leukocyte antigen B27 (HLA-B27).

Adults 18 to 50 years of age:

• A male or female between, and including, 18 and 50 years of age at the time of thefirst study intervention administration.

• Female participants of non-childbearing potential may be enrolled in the study.Non-childbearing potential is defined as pre-menarche, current bilateral tuballigation or occlusion, hysterectomy, bilateral ovariectomy or post-menopause.

• Female participants of childbearing potential may be enrolled in the study, if theparticipant:

• has practiced adequate contraception for 1 month prior to study interventionadministration, and

• has a negative pregnancy test on the day of study intervention administration,and

• has agreed to continue adequate contraception during the entire treatmentperiod and for 1 month after completion of the study interventionadministration series.

• Participants seronegative for human immunodeficiency virus (HIV).

Children 24 to 59 months of age:

• A male or female between, and including, 24 and 59 months of age at the time offirst vaccination.

• Normal nutritional Z score (-2 standard deviation or greater).

• Previously completed routine childhood vaccinations to the best knowledge of theparticipant's parent(s)/LAR(s).

• Born after gestation period of ≥37 weeks.

• Participants seronegative for HIV.

Infants 9 months of age:

• A male or female 9 months of age at the time of first vaccination.

• Normal nutritional Z score (-2 standard deviations or greater).

• Previously completed routine childhood vaccinations to the best knowledge of theparticipant's parent(s)/LAR(s).

• Born after a gestation period of ≥37 weeks.

• Participants negative for HIV as confirmed by deoxyribonucleic acid (DNA) polymerasechain reaction (PCR) testing.

Exclusion Criteria:

All participants:

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

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

• Progressive, unstable or uncontrolled clinical conditions.

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

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

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

• Clinical conditions representing a contraindication to IM vaccination and blooddraws.

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

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

• The participant can still be enrolled into the study at a time when the acutedisease 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 firstadministration of study vaccines (Day -30 to Day 1).

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

• Administration of long-acting immune-modifying drugs at any time during the studyperiod (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 medicaldevice)* other than the study vaccine during the period starting 30 days before thefirst dose of study intervention (Day -30 to Day 1), or planned use during the studyperiod.

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

• A vaccine not foreseen* by the Study Protocol administered during the periodstarting 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 allparticipants 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 studyperiod, in which the participant has been or will be exposed to an investigationalor 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, hepaticor renal functional abnormality, as determined by physical examination or laboratoryscreening tests.

• Chronic administration (defined as more than 14 days in total) of immunosuppressantsor other immune-modifying drugs during the period starting 3 months prior to thefirst vaccine study intervention. For corticosteroids, this will mean prednisoneequivalent ≥20 mg/day for adult participants. Inhaled and topical steroids areallowed.

• Pregnant or lactating female.

• Female planning to become pregnant or planning to discontinue contraceptiveprecautions.

• 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 renalfunctional abnormality, as determined by physical examination or laboratoryscreening tests.

• Chronic administration (defined as more than 14 days in total) of immunosuppressantsor other immune-modifying drugs during the period starting 3 months prior to thefirst 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 andtopical 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.