Estimating the Failure Risk of Hotel-based Quarantine for Preventing COVID-19 Outbreaks in Australia and New Zealand

Grout, L. M.; Katar, A.; Ait Ouakrim, D.; Summers, J. A.; Kvalsvig, A.; Baker, M. G.; Blakely, T.; Wilson, N.

Aim: With increasing global use of hotel-based quarantine as part of COVID-19 border control efforts, we aimed to assess its risk of failure. Methods: We searched official websites in both Australia and New Zealand (NZ) to identify outbreaks and border control failures associated with hotel quarantine (searches conducted up to 12 February 2021). We used two denominators: a) the estimated number of travelers who went through these facilities during the 2020 year up to 31 January 2021; and b) the equivalent number of SARS-CoV-2 positive people who went through these facilities. Results: Up to 31 January 2021, Australia had seven failures with one causing over 800 deaths and six resulting in lockdowns. In NZ there were nine failures, with one causing an outbreak with three deaths, and also a lockdown. The overall failure risk for those transiting quarantine was estimated at one failure per 20,702 travelers and one failure per 252 SARS-CoV-2 positive cases (both countries combined). At the country level, there were 15.5 failures per 1000 SARS-CoV-2 positive cases transiting quarantine in NZ (95%CI: 5.4 to 25.7), compared to 2.0 per 1000 SARS-CoV-2 positive cases in Australia (0.5 to 3.5), a greater than seven-fold difference in risk. Approaches to infection control and surveillance in hotel quarantine were found to vary widely by country and by state/territory. Conclusions: There appears to be a notable risk of failure with the use of hotel quarantine in these two countries. The large variation in infection control practices suggests opportunity for risk reduction.