Do policies that allow access to unregistered antimicrobials address the unmet need? Australia as a case study of a high-income country with universal healthcare.

Background: Ensuring timely and equitable access to effective and optimal antimicrobials is crucial for optimal patient care, to minimize the use of less appropriate treatment options and reduce the risk of antimicrobial resistance (AMR).

Objectives: To determine the average time for new antibacterials to gain registration for use in Australia after obtaining marketing approval internationally, and to quantify the use of 'new' and older unregistered antimicrobials in Australian clinical practice between 2018 and 2023.

Methods: Two data sources were utilized to estimate the usage of antimicrobials not registered for use in Australia.