Public health interventions successfully mitigated multiple incursions of SARS-CoV-2 Delta variant in the Australian Capital Territory

Abstract

This level of detail was only accessible because of the high rate of SARS-CoV-2 sequencing, with sequencing attempted on 1438/1793 (80%) of cases and sequences of appropriate quality for downstream analyses recovered from >75% of all cases.• Transmission chains varied in size and duration, with two dominant incursions (ACT.19 and ACT.20) comprising 35% and 53% of all sequenced cases during the study period, respectively.• The ACT.20 outbreak persisted longer, due to specific challenges with implementing public health interventions in the affected populations.• Both major incursions were successfully curbed through stringent public health measures, including the widespread acceptance of COVID-19 vaccines (>95% of the eligible population by the end of the study period).