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Updated: Dec 31, 2025
Author Spotlight: Rabies-Specific Antibody Isotypes Detection in Sera or Cerebral Spinal Fluid Using an IFA Test
Published on: January 19, 2024
Factors influencing the immune response after a double-dose 2-visit pre-exposure rabies intradermal vaccination
Benjamin Damanet1, Diana Isabela Costescu Strachinaru2, Patrick Soentjens3
1Center for Infectious Diseases, Queen Astrid Military Hospital, Brussels, Belgium; School of Public Health, Free University of Brussels, Brussels, Belgium.
Background:
Double-dose 2-visit intradermal rabies schedules (22ID) have recently been accepted by the World Health Organization (WHO) as Pre-Exposure Prophylaxis (PrEP). The aim of this study is to determine which factors influence the levels of rabies virus neutralizing antibodies (RVNA) after a 22ID rabies vaccination schedule.
Methods:
This is a retrospective study based on electronic health record vaccination data of subjects from the Belgian Armed Forces who received the 22ID rabies PrEP. An antibody titer ≥0.5 IU/mL, measured by rapid fluorescent focus inhibition test, is defined by the WHO as an adequate immune response after PrEP. Logistic regression was performed in order to identify predictive factors of RVNA level ≥3.0 IU/ml and >10 IU/ml.
Results:
301 subjects were included. 297 (98,6%) seroconverted with a RVNA ≥ 0.5 IU/ml. Multivariate analysis shows a significant better immune response in the subjects where the second dose was administered later on than on day 7 (RVNA >10 IU/ml (OR: 3.01 [1.36-6.67])). Postponing the timing of the serology control also influenced significantly the rapid fluorescent focus inhibition test (RVNA ≥ 3.0 IU/ml (OR: 0.12 [0.06-0.24]) and RVNA > 10 IU/ml (OR: 0.14 [0.06-0.29])).
Conclusion:
A 22ID rabies PrEP vaccination schedule is highly effective and provides an adequate immune response in most subjects in a real live setting. Timing of the second vaccine dose significantly influences the response to ID rabies vaccine. Timing of RVNA determination is important in order to correctly assess the response to vaccination.
