Comparison of immunogenicity and safety between two paediatric TBE vaccines

Area of Science:

• Pediatric Vaccinology
• Immunology
• Public Health

Background:

• Tick-borne encephalitis (TBE) poses a significant public health concern, necessitating effective vaccination strategies for children.
• Current TBE vaccines for pediatric use require ongoing evaluation for optimal immunogenicity and safety profiles.

Purpose of the Study:

• To compare the immunogenicity and safety of two European pediatric TBE vaccines: FSME-IMMUN Junior and Encepur Children.
• To assess vaccine responses following a two-dose administration in children aged 1-11 years.

Main Methods:

• A single-blind, multi-center, randomized, controlled, phase III clinical trial.
• Involved 303 children aged 1-11 years, randomized to receive two doses of either FSME-IMMUN Junior or Encepur Children.
• Immunogenicity assessed via immunological tests and viral antigen analysis; safety evaluated through systemic and local reaction monitoring.

Main Results:

• FSME-IMMUN Junior consistently induced higher immunological responses across all tested immunological assays and viral antigens compared to Encepur Children.
• FSME-IMMUN Junior was non-inferior to Encepur Children regarding neutralizing antibody (NT) seropositivity rates (p<0.0001).
• Systemic reactions were infrequent and comparable between vaccines. However, children aged 7-11 years experienced significantly higher local reactions with Encepur Children (49.0% after first dose, 51.0% after second) versus FSME-IMMUN Junior (22.4% after first dose, 10.2% after second).

Conclusions:

• FSME-IMMUN Junior exhibits superior immunogenicity compared to Encepur Children in pediatric populations.
• Both vaccines demonstrate acceptable safety profiles, though Encepur Children is associated with increased local reactogenicity in older children (7-11 years).
• These findings inform TBE vaccination strategy selection for children in endemic regions.