23 September 2021

Updated modelling exploring how high rates of vaccine coverage might reduce the health burden from COVID-19 if combined with moderate public health measures to reduce transmission of the virus.

Aotearoa New Zealand is on track to vaccinate upwards of 80% of those aged over 12 against COVID-19 with the Pfizer/BioNTech mRNA vaccine. Recent announcements by Pfizer and BioNTech suggest that the vaccine may soon be approved for use in children aged 5-11 years. This means it is possible that Aotearoa could achieve vaccine coverage across the total population of more than 90%.

We consider how these high rates of coverage might reduce the health burden from COVID-19 if combined with moderate public health measures to reduce transmission of the virus. Scenarios are evaluated using the Te Pūnaha Matatini vaccine model, using current data about vaccine effectiveness with respect to the Delta variant. As the effects of the vaccine on transmission remain uncertain, we consider three levels of vaccine effectiveness: high, central, and low to illustrate a range of possibilities.

The results suggest that a combination of high levels of vaccination within the community, a strong test-trace-isolate-quarantine system (assuming case numbers are kept sufficiently low) and moderate public health measures may be enough to attain population immunity, greatly reducing the need for strong public health measures, such as stay-at-home orders and workplace closures.