D.5 Implication­s for the next pandemic

As stated at the outset of this appendix, decision-making on when to loosen PHSMs is extremely challenging and requires the balancing of many criteria. This appendix outlines one additional – albeit important – criterion that should be considered in the next pandemic, if the vaccines have notable waning.

Our analyses and modelling for this paper has used New Zealand vaccine coverage data to illustrate the methodology and the value of undertaking such analysis during an evolving pandemic. In the next pandemic, real-time analysis would need to include an additional step of forecasting the likely administration of vaccines over eight or so weeks to be able to forecast forward population immunity and assist decision-making. This additional forecasting need not be difficult. For example, for COVID-19 in New Zealand, the time gap between first and second dose was four weeks up to 12 August 2021, then six weeks. Thus, it would be straightforward to use first dose receipt to forecast second dose receipt in four to six weeks with high accuracy, and then to forecast further weeks based on trends in first dose administration and second dose conversion.