Robust estimates of the case fatality rate of COVID-19 put it under one per cent. To provide some context, the Black Death is said to have killed 60 percent of the European population. The Spanish flu killed 50 million people with a death rate of 10 per cent. HIV/AIDS has killed 35 million people. As many as 575,000 people could have died from H1N1 in its first year of circulation. Seasonal flu kills less than one percent of infected individuals. The COVID-19 death rate appears to be concentrated amongst elderly and immuno-compromised individuals and skewed somewhat towards males.
COVID-19 is highly contagious. Here the important statistic is known as R0 (R-naught). Writing in The Conversation University of Michigan Professor of Epidemiology Joseph Eisenberg describes R0 as follows “the number of cases, on average, an infected person will cause during their infectious period”. So if disease had an R0 of 2, then each infected person would in turn infect two other people. Professor Eisenberg reports that current estimates for the COVID-19 R0 is between 1.5 and 3.5. To provide some context, the R0 for H1N1 is estimated to be between 1.46 and 1.48, the R0 for the seasonal flu is between 2 and 3.
The thing to understand is that R0 is not a constant – it is time-varying. The Centre for the Mathematical Modelling of Infectious Diseases at the London School of Hygiene & Tropical Medicine has estimated R0 for several countries – including Australia. (HT: Marginal Revolution)
If this estimate is correct – the ‘war’ against COVID-19 was won in Australia nearly 3 weeks ago.