The objectives of this first-in-human is to evaluate the safety and the immunogenicity of three administrations of a bivalent vaccine candidate against human cytomegalovirus, at three different dose levels.

Hookipa Biotech AG is developing a replication-deficient lymphocytic choriomeningitis virus (rLCMV) vector platform. HB-101 is a bivalent vaccine containing two recombinant, replication-deficient lymphocytic choriomeningitis virus (rLCMV) vectors, one expressing the pp65 protein of the human cytomegalovirus (HCMV) and one expressing the gB protein of human cytomegalovirus (HCMV).

This Phase 1 will enroll three successive cohorts of 18 healthy volunteers. Each cohort will receive either a low dose, a middle dose or a high dose of the vaccine (n=14 volunteers), or placebo (n=4). A DSMB will review the safety data for the low dose cohort, before progressing to the middle, and so before high dose. Eight DSMB meetings have been planned for the whole study.

The subjects will be followed up to 12 months post first administration.

Inclusion Criteria:

• Signed informed consent
• Male or female, aged 18-45 years, in good health.
• Negative for HCMV
• Body mass index between 19 and 32 kg/m²
• Willing to forego receipt of other routine vaccinations (with the exception of seasonal influenza vaccination) for five months after study entry.
• For female volunteers: use of effective birth control for at least 2 months prior to study entry and willing to use effective birth control measures up to the Month 12 visit
• Comply with the requirements of this protocol (e.g. return for follow-up visits), as judged by the Investigator.

Exclusion Criteria:

• Works as a childcare provider.
• Pregnant or breastfeeding woman.
• Any screening safety laboratory value that is 2 times above the upper limit of normal value.
• Any confirmed or suspected immunodeficiency or autoimmune disorder.
• Treatment with any chronic immunosuppressive medication or other immuno-modifying drugs within 6 months prior to study entry. However, inhaled and topical steroids are allowed.
• Any vaccination other than for seasonal influenza within 3 months prior to study entry.
• Previous vaccination with an investigational HCMV vaccine.
• Receipt of blood, blood products and/or immunoglobulins within 3 months prior to study entry.
• History of severe allergic reactions and /or anaphylaxis
• Allergy to any component of the vaccine preparation.
• Expected to be unavailable to complete study follow up.
• Tested positive for HIV, HBsAg and/or anti-HCV.
• Participating in another clinical trial.
• Subject with a rash, dermatological condition or tattoos in the area of the injection site, as these may interfere with administration site reaction rating.