Suppression and Mitigation Strategies for Control of COVID-19 in New Zealand

Alex James; Shaun C Hendy; Michael J Plank; Nicholas Steyn

• Relative infectious in the pre-symptomatic period is 15% of that in the symptomatic period (Wilson et al. 2020) , although it is possible this is an underestimate (Gayani et al, 2020). • An overall infection fatality rate (IFR) of 1% provided the number of current ICU admissions is below hospital ICU capacity; when ICU is over capacity the excess infections have a 2% fatality rate. The IFR range of 1-2% spans the range estimated using age-specific fatality rates published by the Centre for Disease Control (CDC, 2020) combined with the age distribution of the New Zealand population (StatsNZ) -see Table 1 . Wilson et al (2020) assumed an IFR of 0.9%. • A testing rate for symptomatic infections of 0.1 day -1 . This is equivalent to assuming that 50% of infections are tested before either recovery or death and 50% of infections go untested. In reality, this ratio will vary depending on the number of current infections and the testing capacity and protocols, but most of our results are not sensitive to this assumption. • Model simulations were initialised with 20 seed exposed infections introduced on 1 March 2020 (and no subsequent imported infections). . CC-BY-NC-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.