Immunogenicity of Single-visit, Two-site Intradermal Pre-exposure Rabies Prophylaxis in Children: A Prospective Interventional Study.

BACKGROUND

Rabies remains a major public health concern in endemic countries, particularly among children. Simplified pre-exposure prophylaxis (PrEP) schedules may improve feasibility and access in resource-limited settings and facilitate the integration of rabies vaccination into routine childhood immunization, school-based and community-based vaccination programs in rabies-endemic regions. However, pediatric data on single-visit, 2-site intradermal PrEP regimens remain limited. This study evaluated the immunogenicity and safety of a single-visit, 2-site intradermal rabies PrEP regimen in children 1-18 years of age on days 28 and 180.

METHODS

This prospective single-arm study enrolled healthy children 1-18 years old at a tertiary care center. Participants received a single-visit, 2-site intradermal rabies PrEP regimen with a Vero cell culture rabies vaccine (RABIVAX-S®). Anti-rabies glycoprotein immuglobulin G antibody concentrations were measured using enzyme-linked immunosorbent assay, and rabies virus neutralizing antibody concentrations were estimated by Rapid Fluorescent Focus Inhibition Test at baseline, day 28 and day 180. Participants with rabies virus neutralizing antibody concentrations <0.5 IU/mL at day 28 or day 180 received 2 intradermal booster doses on days 0 and 3 after laboratory results became available and participants returned for follow-up, followed by repeat antibody assessment 7 days after the first booster dose. The primary outcome was seroprotection (≥0.5 IU/mL).

RESULTS

Forty-eight children were enrolled, of whom 44 were evaluated on day 28. The enrolled cohort comprised participants 2-15 years old. On day 28, 40/44 (90.9%) achieved protective antibody concentrations (≥0.5 IU/mL). Among 40 participants included in the day 180 analysis, 27 (67.5%) maintained protective concentrations. All participants with insufficient concentrations (n = 4 on day 28, n = 13 on day 180) demonstrated robust anamnestic responses following booster administration, achieving 100% seroprotection within 7 days. The regimen was well tolerated, with only mild local adverse events reported.

CONCLUSIONS

Single-visit, 2-site intradermal rabies PrEP demonstrated high early seroprotection and preserved immunologic priming despite declining antibody concentrations at 6 months. These findings support further evaluation of simplified pediatric PrEP regimens in larger controlled studies.