Study to Evaluate the Safety, Tolerability and Immunogenicity of a Potential Enteric Fever Vaccine

Inclusion Criteria

To be confirmed at Screening

• Healthy male and female participants 18 to 45 years of age, inclusive.
• Female participant of childbearing potential willing to use 2 effective methods of contraception, i.e., established method of contraception + condom, if applicable (unless of non-childbearing potential or where abstaining from sexual intercourse is in line with the preferred and usual lifestyle of the participant) from the first dose until 2 months after the last dose of Investigational Medicinal Product (IMP).
• Female participant of non-childbearing potential. For the purposes of this study, this is defined as the participant being amenorrhoeic for at least 12 consecutive months or at least 4 months post-surgical sterilisation (including bilateral fallopian tube ligation or bilateral oophorectomy with or without hysterectomy).
• Female participant of childbearing potential or non-childbearing potential with a negative pregnancy test at Screening.
• Female participant of post-menopausal status confirmed by demonstrating at Screening that the serum level of the follicle stimulating hormone (FSH) falls within the respective pathology reference range. In the event a participant's menopausal status has been clearly established (for example, the participant indicates she has been amenorrhoeic for 10 years, confirmed by medical history, etc), but serum FSH levels are not consistent with a postmenopausal status, determination of the participant's eligibility to be included in the study will be at the Investigator's discretion following consultation with the Sponsor.
• Male participant willing to use an effective method of contraception or 2 effective methods of contraception, i.e., established method of contraception + condom, if applicable (unless anatomically sterile or where abstaining from sexual intercourse is in line with the preferred and usual lifestyle of the participant) from first dose until a stool sample tested for presence of the vaccine strains is negative.
• Participant with a body mass index (BMI) of ≥ 19 or ≤34 kg/m^2 (BMI = body weight (kg) / [height (m)]^2).
• No clinically significant history of liver or active gall bladder disease.
• No clinically significant history of ongoing gastro-intestinal disease or abnormality.
• No clinically significant history of previous allergy / sensitivity to ZH9/ZH9PA or sodium bicarbonate.
• No clinically significant history of anaphylactic shock following vaccination.
• No clinically significant history of hypersensitivity (e.g., hives/rash/swollen lips/difficulty with breathing) to azithromycin, ampicillin, trimethoprim-sulfamethoxazole or ciprofloxacin.
• No clinically significant abnormal laboratory test results (in the opinion of the investigator) for serum biochemistry, haematology and/or urine analyses within 28 days before receiving the first dose administration of the IMP.
• Participant with a negative urinary drugs of abuse (DOA) screen (including alcohol and cotinine) test results, determined within 28 days before the first dose administration of the IMP unless there is a documented medical explanation for the positive result other than drugs of abuse (e.g., the participant has been prescribed opioids for pain). (N.B.: A positive test result may be repeated at the Investigator's discretion).
• Participant with negative human immunodeficiency virus (HIV), hepatitis B surface antigen (HBsAg)) and hepatitis C virus antibody (HCV Ab) test results at Screening.
• No clinically significant abnormalities in 12-lead electrocardiogram (ECG) or vital signs determined within 28 days before first dose of IMP.
• Participant must be available to complete the study (including all follow up visits).
• Participant must be willing to consent to have data entered into The Over Volunteering Prevention System (TOPS).
• Participant must provide written informed consent to participate in the study.

To be re-confirmed on Day 0 / prior to