Safety and Immunogenicity of Norovirus GI.1/GII.4 Bivalent Virus-Like Particle Vaccine in an Elderly Population

Inclusion Criteria

• Is aged 18 to 49 years, or 60 years and older at the time of enrollment;
• Participants who are in good health, or in stable health status with no exclusionary medical or neuropsychiatric conditions at the time of entry into the trial as determined by medical history, physical examination (including vital signs) and clinical judgment of the Investigator;
• Participant signs and dates a written, Informed Consent Form (ICF) and any required privacy authorization prior to the initiation of any trial procedures, after the nature of the trial has been explained according to local regulatory requirements;
• Participants who can comply with trial procedures and are available for the duration of follow-up.

Exclusion Criteria

• Has a known hypersensitivity or allergy to any of the Norovirus (NoV) GI.1/GII.4 Bivalent virus-like particle (VLP) Vaccine components;
• Has a clinically significant active infection (as assessed by the Investigator) or body temperature ≥38°C/100.4°F within 3 days of the intended date of vaccination;
• Participants with the presence of significant acute or chronic, uncontrolled medical or neuropsychiatric illness. Uncontrolled was defined as:

Requiring institution of new medical or surgical treatment within 3 months prior to immunization, or Requiring a change in medication dosage in the 3 months prior to immunization due to uncontrolled symptoms or drug toxicity (elective dosage adjustments in stable participants were acceptable), or Hospitalization or an event fulfilling the definition of a serious adverse event within 3 months prior immunization.

• Has any unstable medical or neuropsychiatric condition, which in the Investigator's opinion poses a risk of unusual magnitude for the participant's age group of hospitalization, death, or an event meeting the definition of a serious adverse event within 2 months of immunization. The intent of this criterion is to recognize and allow for the frequent existence of significant health concerns in this population; but exclude those participants who are experiencing an acute decline in health status;
• Has any medical or neuropsychiatric condition, which in the Investigator's opinion, rendered the participant incompetent to provide informed consent or unable to provide valid safety observations and reports;
• Has behavioral or cognitive impairment or psychiatric disease that, in the opinion of the Investigator, may interfere with the participant's ability to participate in the trial;
• Participants with any history of progressive or severe neurologic disorder, history of seizure, or history of neuro-inflammatory disease (e.g. Guillain-Barre syndrome);
• Participants with history or any illness that, in the opinion of the Investigator, might interfere with the results of the trial or pose additional risk to the participants due to participation in the trial;
• Has known or suspected autoimmune disease;
• Has known or suspected impairment/alteration of immune function, including:

Chronic use of oral steroids (Equivalent to 20 mg/day prednisone ≥ 12 weeks/≥ 2 mg/kg body weight/day prednisone ≥ 2 weeks) within 60 days prior to Day 1 (use of inhaled, intranasal, or topical corticosteroids is allowed).

Receipt of parenteral steroids (Equivalent to 20 mg/day prednisone ≥ 12 weeks/≥ 2 mg/kg body weight/day prednisone ≥ 2 weeks) within 60 days prior to Day 1.

Receipt of immunosuppressive therapy within 3 months prior to Day 1. Receipt of immunostimulants within 60 days prior to Day 1. Receipt of parenteral, epidural or intra-articular immunoglobulin preparation, blood products, and/or plasma derivatives within 3 months prior to Day 1 or planned during the full length of the trial.

Human Immunodeficiency Virus (HIV) infection or HIV-related disease. Genetic immunodeficiency.

• Has abnormalities of splenic or thymic function;
• Has any significant disorder of coagulation or treatment with anticoagulant therapy that would increase t