A Phase 2 Study to Evaluate JCXH-105, an srRNA-based Herpes Zoster Vaccine

Key Inclusion Criteria:

• Sex: Male or female; female subjects may be of childbearing potential, ofnonchildbearing potential, or postmenopausal.

• Age: ≥ 50 years of age at screening.

• Status: Healthy subjects.

• Subjects must agree to not be vaccinated with any HZ vaccine while participating inthis study.

• Subjects must agree to not be vaccinated with any RNA-based vaccines (e.g.,Spikevax, Comirnaty, etc.) 30 days before Dose 1 through 30 days after Dose 2 (a 4-month period).

Key Exclusion Criteria:

• Subjects with a history of HZ within the past 10 years or current diagnosis of HZ.

• Previous vaccination against HZ.

• Subjects with any respiratory illness deemed clinically relevant by the Investigatorwithin the past month OR hospitalization >24 hours for any reason within the pastmonth prior to the first vaccine administration (JCXH-105 or Shingrix).

• Subjects who are acutely ill or febrile with body temperature ≥ 38.0º Celsius/100.4ºFahrenheit 72 hours prior to or at the Screening visit or on Day 1 pre-dose.Subjects meeting this criterion may be rescheduled within an allowable window withapproval from the Sponsor.

• Subjects with history or current diagnosis of congenital or acquiredimmunodeficiency/immunocompromising/immunosuppressive conditions, asplenia, orrecurrent severe infections. Certain immune-mediated conditions (e.g., Hashimotothyroiditis) that are well controlled and stable are allowed.

• Subjects with history of myocarditis or pericarditis, or with AEs (includinganaphylaxis and severe hypersensitivity) after mRNA vaccination that are in natureand severity beyond the common expected AEs and necessitating medical intervention.

• Subjects who received any non-live vaccine within 14 days prior to Day 1 (first doseof JCXH-105 or Shingrix).

• Subjects who received within 28 days prior to Day 1 (first dose of JCXH-105 orShingrix): (1) Any live vaccine, (2) Immunomodulators or immune-suppressivemedication, (3) Granulocyte or granulocyte-macrophage colony-stimulating factor, (4)Three or more consecutive days of systemic corticosteroids. Note: subjects onstable-dose steroid replacement (for chronic disease such as iatrogenic deficiency)of prednisone ≤10 mg/day or equivalent are allowed and (5) Other investigationalagents or devices.

• Subjects receiving systemic antiviral therapy.

• Subjects with a positive screening test for hepatitis B surface antigen (HBsAg),hepatitis C virus (HCV) antibodies, anti-human HIV-1 and 2 antibodies, or syphilis.

• Subjects with a positive screening test for severe acute respiratory syndromecoronavirus 2 (SARS-CoV-2).