*2.4. Public Health Interventions*

Before the outbreak was identified, routine targeted vaccination programs run by the LMPHU vaccination outreach team meant that by the time the outbreak was declared on the 8 January 2022, all workers had received at least 2 doses of the Pfizer-BioNTech (COMIRNATY) vaccine. None of the workers were reported to have had their last dose of COVID-19 vaccination more than 6 months or less than 10 days before outbreak declaration (considered for vaccine protection efficacy) or had COVID-19 infection 6 weeks prior (considered re-infection window at the time of the outbreak) [13]. Immediately after receiving the outbreak notification, which occurred late on a Saturday afternoon, the farm was contacted by one of the LMPHU public health officers to undertake a risk assessment; this assessment identified that the seasonal workers lived onsite in accommodation that consisted of a single or double room, with shared facilities and communal spaces. The pathology provider was then contacted and requested to assist in performing onsite-testing for all workers; they delivered seventy rapid-antigen-testing kits the next day. Further testing was subsequently undertaken on the fourth and sixth days on all workers who had previously tested negative to COVID-19 to ensure that any late onset infections were ruled out. The cultural and language support services assisted in providing instructions for performing a RAT to all workers and also provided pastoral care support to all onsite. The IPCAR and IPC consultant liaised with the farm management to ensure that appropriate infection control measures were in place to limit infection transmission among workers. An outbreak management team (OMT) was established to discuss with all stakeholders and workers the optimal measures to manage the outbreak. During this meeting after consulting with the LMPHU medical leads, it was determined that all symptomatic workers would be treated as COVID-19-positive due to the delays in obtaining the results of COVID-19 PCRs that were occurring at the time. The local tertiary public hospital supported the outbreak by performing a clinical assessment on cases as they were identified; they then met with the site daily during the outbreak to monitor the clinical status of all cases.

#### **3. Results**
