Immunogenicity of Three-session Intradermal Rabies Post-exposure Prophylaxis in Indian Children and Adolescents

Rabies is a uniformly fatal but vaccine-preventable disease. In India, the standard 4-session intradermal rabies post-exposure prophylaxis is currently administered. The World Health Organization has recommended a shortened 3-session regimen. Pediatric and adolescent-specific data for this abbreviated protocol remain sparse.

To evaluate the immunogenicity of the 3-session intradermal rabies post-exposure prophylaxis regimen among children and adolescents under 18 years of age in India and to assess its adequacy for potential policy adoption.

A descriptive cross-sectional study was conducted at the Animal Bite Clinic of a tertiary teaching hospital in New Delhi, India. Eighty-two children and adolescents presenting for the 4th rabies vaccine dose were enrolled. Blood samples were collected before administration of the fourth dose, and IgG anti-rabies virus glycoprotein antibody values were estimated using indirect enzyme-linked immunosorbent assay. Values ≥0.5 EU/mL were considered seroprotective. Participants were followed up for 1 year for any development of rabies.

Of the 82 participants, 79 (96.3%) had seroprotective values. The geometric mean value was 2.67 EU/mL. Three participants (3.7%) had values <0.5 EU/mL. Follow-up assessment post-4th dose confirmed seroconversion in 2 of them. The use and type of rabies immunoglobulin had no significant effect on seroconversion. No participants developed rabies over a 1-year follow-up.

Although seroconversion was achieved in 96.3% of participants after 3 sessions, the 3.7% with nonprotective values raise concerns. Given the fatal nature of rabies and infrastructural variability in Indian healthcare, continuation of the 4-session regimen is recommended until broader validation is conducted in a representative pediatric population via multicentric studies.