Impact of the Astra Zeneca COVID-19 vaccine on an emergency department.

Objective: To assess the impact of the AstraZeneca (AZ) vaccine roll-out on an ED. Primary outcomes are ED length of stay (LOS), investigation ordering and costs. Secondary measures are compliance with the Thrombosis and Haemostasis Society of Australia and New Zealand (THANZ) Vaccine-Induced Thrombotic Thrombocytopaenia Syndrome (VITT) guidelines.

Methods: This retrospective observational study examined a level 5 ED in Sydney, Australia. Triages mentioning the AZ vaccine between 7 July 2021 and 8 November 2021 were reviewed. Cases were limited to a single day of the week. Researchers reviewed clinical notes to identify patients that presented due to AZ vaccine concern and abstracted relevant data. Costings were calculated using an ED activity-based funding algorithm.

Results: One thousand three hundred and fifty cases were identified, with 167 analysed (12%) and 97 presented (7%). Median LOS was 195 min (IQR: 152-232 min, 95% CI [184, 217]). Median age was 43 years (IQR: 35-65 years, 95% CI [44, 51]). Median Australian Triage Category was 4. Ninety-eight percent were discharged directly home. Ninety-four percent underwent pathology and 41% radiology. Compliance with the THANZ guidelines was 16%. No findings were related to VITT. AZ vaccine concern contributed 12% of August ED caseload. Over the 16-week study period a cost of AUD$486 747.99 was extrapolated.

Conclusions: A high number of young, low acuity patients presented to the ED with AZ vaccine concerns and were associated with financial and workload implications. The quantity of ED presentations appears to be associated with vaccine administration rates. There was poor compliance with the THANZ guidelines, and they appear to have contributed to the high volume of investigations.