Objective:
The emergence of the SARS-CoV-2 Omicron variant has resulted in rapidly increasing case numbers, although incidence of severe disease is decreased. This study aimed to predict the health burden upon the Western Australian hospital system once the hard border is removed and an outbreak occurs, and the change in this health burden over time due to waning vaccination immunity.
Findings:
- Population immunity in Western Australia reaches a peak approximately at the beginning of February 2022 and plateaus for 5 months, until July 2022, before beginning to decline.
- Opening the Western Australian border prior to June 2022 results in the health burden of an outbreak being minimised. For an opening of March 5th 2022 a peak of 510 hospital beds will be required, of which 51 will be in ICU. This is below the estimated surge capacity of Western Australian hospitals of 52 ICU beds. A total of 2,932 hospitalisations, 293 ICU admissions and 383 deaths are predicated.
- Opening the Western Australian border in June 2022 or later will result in greater case loads and consequently a higher burden on the health system. If the border is opened on June 5, 2022, 750 hospital beds are predicated to be required, 75 of which will be in ICU. This is greater than the estimated 52 ICU beds available as surge capacity. In total 3,603 hospitalisations, 360 ICU admissions and 478 deaths are predicated.
Conclusion:
In order to minimise peak daily and total health burden, removal of the Western Australian hard border should be preferred earlier rather than later, prior to June 2022. In doing so, peak ICU demand is predicated to not exceed surge capacity of Western Australian hospitals. On 18th February 2022 the Government of Western Australia announced the borders would be reopened on March 3rd 2022 amid an ongoing local outbreak. While not specifically modelling this scenario, these results are generally applicable to the ongoing outbreak and can be used to estimate progression through the wave.
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