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Remote Laboratory Management: Respiratory Virus Diagnostics
Published on: April 6, 2019
Managing the risk of a COVID-19 outbreak from border arrivals
Nicholas Steyn1,2,3, Michael J Plank1,3, Alex James1,3
1School of Mathematics and Statistics, University of Canterbury, Christchurch, New Zealand.
Abstract:
In an attempt to maintain the elimination of COVID-19 in New Zealand, all international arrivals are required to spend 14 days in government-managed quarantine and to return a negative test result before being released. We model the testing, isolation and transmission of COVID-19 within quarantine facilities to estimate the risk of community outbreaks being seeded at the border. We use a simple branching process model for COVID-19 transmission that includes a time-dependent probability of a false-negative test result. We show that the combination of 14-day quarantine with two tests is highly effective in preventing an infectious case entering the community, provided there is no transmission within quarantine facilities. Shorter quarantine periods, or reliance on testing only with no quarantine, substantially increases the risk of an infectious case being released. We calculate the fraction of cases detected in the second week of their two-week stay and show that this may be a useful indicator of the likelihood of transmission occurring within quarantine facilities. Frontline staff working at the border risk exposure to infected individuals and this has the potential to lead to a community outbreak. We use the model to test surveillance strategies and evaluate the likely size of the outbreak at the time it is first detected. We conclude with some recommendations for managing the risk of potential future outbreaks originating from the border.
Insights
The 14-day quarantine and two-test strategy effectively prevents COVID-19 (coronavirus disease 2019) spread from international arrivals. Shorter quarantine or testing alone significantly raises the risk of community outbreaks.
Area of Science:
- Epidemiology
- Public Health
- Infectious Disease Modeling
Background:
- New Zealand's strategy to eliminate COVID-19 relies on strict border controls, including 14-day quarantine and testing for international arrivals.
- The risk of community transmission seeded at the border necessitates robust modeling of quarantine effectiveness.
Purpose of the Study:
- To model COVID-19 transmission within quarantine facilities and estimate the risk of border-initiated community outbreaks.
- To evaluate the effectiveness of different quarantine durations and testing strategies in preventing infectious cases from entering the community.
Main Methods:
- Utilized a branching process model to simulate COVID-19 transmission.
- Incorporated a time-dependent probability of false-negative test results.
- Analyzed the fraction of cases detected in the second week of quarantine as an indicator of in-facility transmission.
Main Results:
- The combination of 14-day quarantine and two COVID-19 tests is highly effective in preventing infectious cases from entering the community, assuming no in-facility transmission.
- Shorter quarantine periods or testing without quarantine substantially increase the risk of releasing infectious individuals.
- The proportion of cases detected during the second week of quarantine may indicate the likelihood of transmission within facilities.
Conclusions:
- Current quarantine and testing protocols are effective when transmission within facilities is absent.
- Monitoring second-week detections can inform risk assessment for in-facility transmission.
- Recommendations are provided for managing border-related outbreak risks and protecting frontline staff.
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