A First-in-Human Study to Evaluate JCXH-105, an SrRNA-based Herpes Zoster Vaccine

Inclusion Criteria: * Sex: Male or female; female subjects may be of childbearing potential, of nonchildbearing potential, or postmenopausal. * Age: 50 to 69 years of age, inclusive, at screening. * Status: Healthy subjects. Note: Healthy status as defined by the absence of evidence of any clinically significant active or chronic disease, in the opinion of the Investigator, following a detailed medical and surgical history, a complete physical examination including vital signs, 12-lead electrocardiogram (ECG) recording, hematology, blood chemistry, serology, and urinalysis. Healthy subjects may have stable pre-existing disease defined as disease not requiring significant change in therapy or hospitalization for worsening disease during the 6 weeks prior to enrollment. * Subjects must agree to not be vaccinated with any HZ vaccine while participating in this study. * All values for hematology and clinical chemistry tests of blood and urine within the normal range OR showing no clinically relevant deviations based on medical history, considering stable pre-existing diseases (see Healthy Subjects above), as judged by the Investigator. Exclusion Criteria: * Subjects with a history of HZ or current diagnosis of shingles. * Previous vaccination against HZ. * Subjects with any respiratory illness deemed clinically relevant by the Investigator within the past month OR hospitalization \>24 hours for any reason within the past month prior to the first vaccine administration (JCXH-105 or Shingrix). * Subjects with history of myocarditis or pericarditis, or with AEs after mRNA vaccination that are in nature and severity beyond the common expected AEs necessitating medical intervention. * Subjects who have received an mRNA-based vaccine (e.g., Spikevax, Comirnaty, etc.) 30 days prior to Day 1. * Subjects who received any non-live vaccine within 14 days prior to the first vaccine administration (JCXH-105 or Shingrix). * Subjects who received within 28 days prior to first vaccine administration (JCXH-105 or Shingrix): (1) Any live vaccine, (2) Immunomodulators or immune-suppressive medication, (3) Granulocyte-macrophage colony-stimulating factor, (4) Three or more consecutive days of systemic corticosteroids. Note: subjects on stable-dose steroid replacement (for chronic disease such as iatrogenic deficiency) of prednisone ≤10 mg/day or equivalent are allowed, and (5) Other investigational agents or devices. * Subjects with active or suspected immunosuppression, immunodeficiency, or autoimmune disease. * Subjects receiving systemic antiviral therapy. * Subjects with a positive screening test for hepatitis B surface antigen (HBsAg), hepatitis C virus (HCV) antibodies, or anti-human HIV-1 and 2 antibodies. * Subjects with a positive screening test for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). * Subjects with a known history of active or latent tuberculosis (bacillus tuberculosis).