This may be only of curiosity value, but I've been collecting statistics from the twice-daily bulletins on Covid-19 published by the Commonwealth Deptartment of Health at https://www.health.gov.au/news/health-alerts/novel-coronavirus-2019-ncov-health-alert/coronavirus-covid-19-current-situation-and-case-numbers
The initial phase from 29th Feb. to 27th March was an almost perfect exponential: n = 19.25 exp(0.19t) where 'n' is the cumulative number of notified cases and 't' is the number of days since 29th February, and the Pearson correlation is 1.00. This is what we'd expect in the early stages of a pandemic when there's no significant population immunity. However the period since 27th March is best described by a polynomial, also with a correlation of 1.00: n = -14.27(t²) + 1,196(t) - 19,010 If it continues to be accurate the rate of new infections will drop to zero in a few days, when there will have been a total of 6,050. The trend line obviously isn't useful after that since the cumulative total would begin to decrease. However it raises an interesting policy decision. The current constraints can't go on forever, but to what extent should the rules be relaxed? I think the national border should definitely remain closed, but should there be no relaxation pending possible release of a vaccine? Or should the rules be managed so everyone gets a dose of covid‑19, but slowly? Would that be too risky? It's reported the medical panel and Government is considering the latter. David l. _______________________________________________ Link mailing list Link@mailman.anu.edu.au http://mailman.anu.edu.au/mailman/listinfo/link
