Model Projections for 'Opening Up' in NSW
The graph shows an incomplete analysis of Covid-19 cases in NSW. Vaccine efficacies have been taken into account, but the reinfection of recovered cases has not yet been taken into account. When it is taken into account the 'susceptible' number will increase, increasing the numbers infected, but not the total number of individuals who have been infected and not the deaths. That is because the case fatality rate (CFR) is low with reinfection or vaccination and because the total number of individuals infected does not increase after the first infection.
The current wave in NSW is producing about 1300 new cases daily with an effective R (effR or R8) of 1.3 (after taking vaccination into account). The Model suggests that there will be a cumulative total of 99,000 NSW cases (an increase of 60,000 during this delta Covid-19 wave.
The current wave in NSW is producing about 1300 new cases daily with an effective R (effR or R8) of 1.3 (after taking vaccination into account). The Model suggests that there will be a cumulative total of 99,000 NSW cases (an increase of 60,000 during this delta Covid-19 wave.
The projected effeR or projected R8 is used to drive the Model and the graph because, in our humble opinion, it is a good single summary measure of all the factors that drive an epidemic, including R0, public compliance, reactions by health authorities, vaccine hesitancy and others. So the projected R8 is an input assumption. It is expected to continue to decrease as it is, then stabilise once 70% adult fully vaccinated is reached and then increase to the R0 of delta Covid (about 5.5). The Model is mathematical and probably robust, but humans are predictably unpredictable. It is possible that the surge in cases and coming surge in deaths will increase vaccination rates; but it has not done so in the US and UK. Hopefully children under 12 will be allowed 'off label' vaccination to prevent the likely 80 deaths in isolation in ICU without a parent in unvaccinated children (and later a potential 350 childhood deaths in aged under 12 in Australia, since maintaining effective closed land borders is very difficult.
