Drivers of rabies post-exposure prophylaxis noncompletion in Cambodia, 2019 to 2022

Achieving the "Zero by 30" goal-zero human deaths due to dog-mediated rabies by 2030-depends heavily on the timely and complete administration of post-exposure prophylaxis vaccination (PEPV) to exposed individuals. This study aims to assess trends and evaluate rabies PEPV noncompletion following the introduction of the abridged 1-week protocol, and identify its drivers in Cambodia, which bears a high rabies burden.

A retrospective analysis of patients attending the three Institut Pasteur du Cambodge (IPC) rabies prevention centers (RPCs) between 2019 and 2022 was conducted to assess exposure categories and PEPV completion. Multivariate regression was used to identify factors associated with noncompletion.

Among the 239,874 patients with a category II or III exposure requiring PEPV who attended the three IPC RPCs from 2019 to 2022, 6.4% did not complete the full three-session PEPV regimen or the two-session regimen for the previously immunized patients. Greater travel time to the RPC was strongly associated with lower attendance and completion rates. In addition, noncompletion was more common among males and working-age youth (15-29). Attendance and completion dropped sharply during Covid-19 mobility restriction periods and, conversely, rose markedly following a social media event publicizing a rabies-related death in 2019. Other factors significantly associated with PEPV noncompletion included year of PEPV administration, RPC location, species of the biting animal, health and living status, mode of attack and type of attack, and time between exposure and the first PEPV dose received.

Although overall PEPV noncompletion rates were low at IPC's RPCs, this study revealed significant temporal and spatial variations. Travel time to RPC emerged as a major barrier to both RPC attendance and PEPV completion, underscoring the need to decentralize PEPV delivery to reduce access inequities. High-risk groups, particularly males and youth (15-29), would benefit from targeted communication strategies and flexible service hours. These findings can inform rabies prevention strategies in Cambodia by guiding the development of more equitable and effective PEPV delivery systems-critical to achieve the "Zero by 30" goal.