Prof Nick Wilson, Dr Matthew Parry, Dr Ayesha Verrall, Prof Michael Baker, Prof Martin Eichner (author details*)
This blog details a recent modelling study we conducted. In it we estimated that it would take between 27 and 33 days of no new detected cases of COVID-19 for there to be a 95% probability of epidemic extinction in NZ (at around current testing levels). For a 99% probability of epidemic extinction, the equivalent time-period was 37 to 44 days. So now the country urgently needs the Ministry of Health to provide an official definition of elimination and to upgrade the data on its website so that the public, the media and researchers can monitor progress towards achieving the goal.
Prof Nick Wilson, Dr Sophie Febery, Dr Ling Chan, Dr Amanda Kvalsvig, Prof Michael Baker
In this blog we identify six likely benefits from requiring fabric mask use in public transportation and border control settings in the “peri-elimination” context that New Zealand is currently in. Given these likely benefits and the relatively low costs (especially if the Government provides free masks as per Hong Kong), such a policy should be given very serious consideration by health authorities in the transition to level 2.
Dr Ling Chan, Dr Sophie Febery
Widespread public mask use is common in some Asian countries as a control measure in the current Covid-19 pandemic. There is some suggestive laboratory and epidemiological evidence of benefit for such mask use. Since the costs of mass masking are relatively low and there are no apparent substantial down-sides, it should be given serious consideration by the NZ Government to speed progress towards the elimination goal.
Prof Rod Jackson (Epidemiologist, Auckland University)
There are really only three ways that a population can beat Covid-19: (i) eliminate the virus and keep infected people out (the approach NZ is taking); (ii) allow a sufficient proportion of the population to get infected and become immune to re-infection so there are no longer enough non-immune people to allow the virus to spread (this is called herd immunity and is estimated to be at least half of any population for Covid-19); or (iii) develop an effective vaccine, which is the ideal way of achieving herd immunity. Given a vaccine might still be a long way off, NZ’s elimination strategy (if successful) is likely to avoid high numbers of deaths and the need for long periods of restrictions to suppress or mitigate the spread of Covid-19.
Nick Wilson,1 Ayesha Verrall,1,2 Len Cook,3 Alistair Gray,3 Amanda Kvalsvig,1 Michael Baker,1 (1epidemiologists, 2infectious disease physician, 3statisticians)
In this blog we raise ideas for how New Zealand might optimise testing to both identify cases in the community as part of the COVID-19 elimination strategy, and to confirm when the virus has been completely eliminated from the country. These are urgent issues to clarify in order to minimise time spent under lockdown conditions and allow the economy and health system to return to more normal functioning. The priority is to continue testing symptomatic people, with the sensitivity of case detection expanded by steadily broadening the case definition and ensuring wide geographic and demographic coverage. After that, testing to assess the elimination goal could involve testing of higher-risk exposed groups, potentially using pooled specimens and serology, along with sewage testing.