Defining the volume of rabies immunoglobulins/ rabies monoclonal antibodies requirement for wound infiltration of category III animal exposures - an exploratory study

Post-Marketing Surveillance of the World's First Novel Cocktail of Rabies Monoclonal Antibodies: TwinRab™ in Real \-World Setting

Rabies presents with a high fatality rate, which imposes a significant global public health challenge, and therefore the use of post-exposure prophylaxis (PEP) is crucial for prevention. Monoclonal antibodies (mAbs) have emerged as a promising substitute for rabies immunoglobulins (RIGs) due to their high efficacy and standardized manufacturing process. A prospective, open-label, post-marketing surveillance study (PMS) was conducted at Byramjee Jeejeebhoy Medical College (BJMC), Pune. The study included patients aged more than 2 years who had recently sustained Category III-suspected rabid animal bite exposures. These patients were administered TwinRabTM at a dosage of 40 IU/kg in and around the wound as intralesional transfer, along with the anti-rabies vaccine (ARV). Adverse events (AEs) grading was performed with reference to the Food and Drug Administration (FDA) toxicity grading. In this study, 215 subjects received the TwinRabTM mAb with a 100% completion rate. Out of 215 patients, three (1.3%) patients in the range of 18 to 65 years of age showed solicited local AEs, which were resolved after the appropriate treatment intervention, but causality assessment was non-assessable. The overall tolerability assessment showed positive ratings from doctors (91.63%) and patients (67.91%) for the mAb cocktail. The PMS demonstrated the safety of TwinRabTM in patients who experienced Category III-suspected rabid animal bites, thereby supporting its potential as an alternative option for post-exposure prophylaxis in the management of animal bites for the prevention of rabies.

Safety and clinical efficacy of human rabies immunoglobulin in post exposure prophylaxis for category III animal exposures

The human rabies immunoglobulin (HRIG) is a life-saving immune biological essential for all category III animal exposures. It provides neutralizing antibodies at the site of exposure until the body can produce vaccine-mediated antibodies. We conducted this study to determine the safety and clinical efficacy of an HRIG being used presently for post-exposure prophylaxis (PEP) and to strengthen the existing evidence for its further usage. We conducted a prospective cohort study in 123 subjects with category III animal exposures at the KIMS Hospital and Research Center, Bangalore, India. Post-exposure prophylaxis (PEP) with wound toilet, a single application of HRIG, and a full course of anti-rabies vaccination were provided to all the study subjects. The volume of HRIG was calculated according to the body weight, and all the wounds were infiltrated as was anatomically feasible. All the study subjects were followed up for immediate and delayed adverse events (AE), both local and systemic. Subsequently, all the subjects were followed up for 6 months to demonstrate the clinical efficacy of PEP. The incidence of AEs was 11.4% including local pain, erythema, itching, headache, body ache, fever, and malaise. All AEs were mild and subsided without any complications. All the study subjects were healthy and alive after 6 months following the administration of HRIG, along with a full course of anti-rabies vaccine. Our study provides evidence of safety and clinical efficacy of HRIG for category III animal exposures and supports its continued usage.

Implementation of Clinical Decision Support on Emergency Department Delivery of Human Rabies Immune Globulin

IMPORTANCE

Fatal human rabies infections can be prevented through appropriate rabies postexposure prophylaxis (PEP). Errors in patient selection and administration of human rabies immune globulin in the emergency department (ED) setting were identified in a previous study of rabies PEP administration.

OBJECTIVE

To test the a priori hypothesis that implementation of a rabies PEP bundle in the ED would improve full adherence to 6 human rabies immune globulin quality indicators compared with preimplementation controls.

DESIGN, SETTING, AND PARTICIPANTS

This quality improvement study was conducted in 15 EDs in a US multihospital health system. Patients who received human rabies immune globulin or rabies vaccine in the ED from January 2015 to June 2018 were included in the preimplementation control group and from December 2019 to November 2020 were included in the postimplementation intervention group. Data were analyzed in January 2021.

EXPOSURE

The PEP bundle was implemented in December 2019 and consisted of electronic health record enhancements, including clinical decision support, ED staff education, and patient education.

MAIN OUTCOMES AND MEASURES

Full adherence to 6 human rabies immune globulin quality indicators: patient selection, dose, timing, infiltration into wounds, administration distant from rabies vaccine site, and administration that avoids the buttock.

RESULTS

The study included 324 patients; 254 patients were in preimplementation group (mean [SD] age, 39 [21] years; 135 [53%] women) and 70 in the postimplementation group (mean [SD] age, 38 [19] years; 33 [47%] women). Most patients presented to EDs embedded in a community hospital (231 patients [71%]). Full adherence increased from 37% in the preimplementation group to 61% postimplementation (absolute increase, 24%; 95% CI, 11% to 37%; P < .001). Adherence improved for quality indicators for infiltration into wounds (137 of 254 patients [54%] to 50 of 70 patients [71%]; P = .009), administration distant from rabies vaccine site (180 of 254 [71%] to 58 of 70 [83%]; P = .04), and administration that avoids the buttock (168 of 254 [66%] to 58 of 70 [83%]; P = .007). No instances of sciatic nerve injury or compartment syndrome were observed.

CONCLUSIONS AND RELEVANCE

In this quality improvement study, implementation of a rabies PEP bundle was associated with improved patient selection and delivery of human rabies immune globulin in EDs across a multihospital health system. Although the bundle included ED staff education and patient discharge education, the observed improvement was likely driven by clinical decision support from the rabies PEP ED order set. Future research should evaluate implementation of this clinical decision support at other health systems.