Wound-Only versus Weight-Based Rabies Immunoglobulin in Post-Exposure Prophylaxis: A Quasi-Randomized Asessor Blind Non-Inferiority Trial

Rabies is a fatal but preventable zoonotic disease that causes more than 20,000 deaths annually in India. Post-exposure prophylaxis (PEP) involves rabies vaccination and passive immunization with rabies immunoglobulin (RIG). Traditional RIG dosing is based on patient weight, whereas wound-only administration targets local viral neutralization at the exposure site. In the present study, antibody responses were compared after a three-dose anti-rabies vaccination in patients receiving either wound-only or weight-based RIG infiltration as part of PEP to assess the noninferiority of the wound-only approach. Patients with category III rabies exposure were enrolled in this noninferiority clinical trial, all of whom received a standard three-dose rabies vaccination. Rabies immunoglobulin was administered either according to body weight or infiltrated only around the wound. Serum rabies-neutralizing antibody titers were measured at predefined intervals. The primary outcome was the proportion of patients exhibiting protective antibody titers; secondary outcomes included RIG usage volume, adverse events, and feasibility in resource-limited settings. Both groups achieved adequate seroconversion with protective antibody titers. Wound-only RIG infiltration produced protective antibody responses comparable to weight-based RIG dosing while substantially reducing RIG volume used and could improve feasibility. Larger studies, including formal cost-effectiveness analyses, are needed to confirm the clinical and programmatic implications.