Immunogenicity and Safety of Three Formulations of Dengue Vaccines in Healthy Adults Aged 18 to 45 Years in the US

All participants provided blood samples for immunogenicity assessments, while vaccine viremia was assessed in a subset of participants in each group.

Safety was assessed in all participants as follows: solicited adverse event (AE) prelisted in the diary card were collected for 7 days after vaccination for solicited injection site reactions and 14 days for solicited systemic reactions , unsolicited AEs were collected for 28 days after vaccination, and serious adverse event (SAE) information collected throughout the study up to 6 months after vaccination.

Inclusion criteria

• Healthy, as determined by medical history, clinical examination, and biological safety parameters.
• Aged 18 to 45 years on the day of inclusion.
• Provision of informed consent signed by the participant or another legally acceptable representative.
• For a woman of child-bearing potential, use of an effective method of contraception or abstinence for at least 4 weeks prior to the first vaccination, and until at least 4 weeks after the last study vaccination.
• Able to attend all scheduled visits and to comply with all trial procedures.

Exclusion criteria

• Personal or family history of thymic pathology (thymoma), thymectomy, or myasthenia.
• For a woman of child-bearing potential, known or suspected pregnancy or positive serum/urine pregnancy test.
• Breast-feeding woman.
• Participation in another clinical trial investigating a vaccine, drug, medical device, or a medical procedure in the 4 weeks preceding the first trial vaccination.
• Planned participation in another clinical trial during the present trial period.
• Known or suspected congenital or acquired immunodeficiency, immunosuppressive therapy such as anti-cancer chemotherapy or radiation therapy within the preceding 6 months, or long-term (at least 2 weeks within the previous 3 months) systemic corticosteroids therapy (at a dose of at least 10 mg). Topical steroids were allowed.
• Known systemic hypersensitivity to any of the vaccine components or history of a life-threatening reaction to the trial vaccine or to a vaccine containing any of the same substances.
• Chronic illness at a stage that could interfere with trial conduct or completion, in the opinion of the investigator.
• Current or past alcohol abuse or drug addiction that may interfere with the participant's ability to comply with trial procedures.
• Receipt of blood or blood-derived products in the past 3 months, that might interfere with the assessment of immune response.
• Receipt of any vaccine in the 4 weeks preceding the first trial vaccination.
• Planned receipt of any vaccine in the 4 weeks following each of the trial vaccinations.
• Human Immunodeficiency Virus (HIV), hepatitis B surface antigen, or hepatitis C virus seropositivity in blood sample taken at Screening.
• Participant deprived of freedom by an administrative or court order, or in an emergency setting, or hospitalized without his/her consent.
• Clinically significant laboratory test abnormalities (as determined by the investigator) in blood sample taken at Screening.
• Previous residence in, travel or planned travel of more than 2 weeks during the study period to areas with high dengue infection endemicity.
• Reported history of flavivirus infection as reported by the participant.
• Previous vaccination against flavivirus diseases (including Japanese encephalitis, tick-borne encephalitis, and yellow fever).
• Flavivirus vaccination planned during the trial period.