1. We have no viable way to sufficiently reduce the risk of an infected person arriving to an acceptable level under normal, unrestricted circumstances - so we must reduce the rate of arrivals to a low enough level that we can apply additional measures.
2. Allowing only citizens & residents brings arrivals to a manageable rate. The probability of a positive case arriving soon (within days) is still 100%.
3. Isolating all arrivals from the rest of the community reduces the risk of community incursion.
4. Arrivals obviously can't all be isolated away from the community indefinitely, so the probability of infected individuals being released needs to be lowered to an acceptable (very small) level.
5. Isolated arrivals must be housed, fed etc, and some of them will be infected. New risks: transmission from isolated individuals to community via provided services in isolation, in transit to isolation facilities, and containment failure.
6. Releasing arrivals after 14 days allows one full transmission cycle. Symptoms are likely to be noticeable within this period. New risks: unnoticed asymptomatic cases, isolated individuals infecting each other.
7. Don't release symptomatic individuals. Addresses: positive cases which do not recover within isolation period.
8. Test isolated individuals at days 3 & 12. Addresses: unnoticed asymptomatic cases, day 3 false negative. New risk: test refusal.
9. Require negative test before release. Addresses: unrecovered positive cases. New risk: test refusal.
10. Isolate test-refusing individuals for further 28 days. Addresses: test refusal.
11. Add security guards. Addresses: containment failure.
12. Add fencing. Addresses: containment failure.
13. Select premises to minimise egress points. Addresses: containment failure.
14. Add police with detainment powers. Addresses: containment failure.
15. Require PPE for guests. Addresses: transmission between guests.
16. Require PPE for staff. Addresses: infection of staff.
17. Frequent health checks for staff. Addresses: transmission to community.
18. Regular testing of staff. Addresses: transmission to community.
19. Criminal penalties for escapees. Addresses: containment failure.
20. Social distancing of guests. Addresses: transmission between guests.
21. Reduce services. Addresses: infection of staff.
22. Contact tracing. Addresses: community spread. New risks: slow tracing reduces effectiveness, missed contacts, unreachable contacts.
23. Community testing. Addresses: community spread. New risks: false negative.
24. Genomic sequencing. Addresses: community spread.
25. Increase tracing staff. Addresses: slow tracing.
26. NZ Covid Tracer app. Addresses: slow tracing, unreachable contacts, missed contacts.
27. Upstream tracing. Addresses: community spread.
28. Move MIQ facilities outside of urban areas. Addresses: impact of containment failure.
29. Confine guests to room. Addresses: transmission between guests.
30. Land flights directly at MIQ. Addresses: transmission in transit.
31. Purpose-built MIQ facilities. Addresses: transmission to staff (because fewer staff needed).