The estimated maximum reduction in the attack rate compared to an unmitigated pandemic ranged between 3-11%, 2-6% and 2-3% for R 0 =1.5, 2.0 and 2.5, respectively (Table 2).
The estimated costs of seasonal epidemics from 1999 2008 in Italy ranged from €1.5 to €2.0 billion per year, and the costs of the H1N1/09 pandemic ranged from €1.3 to €2.3 billion.
The proportion of HCWs unwilling to work in the event of an influenza pandemic ranged from 16 to 85 %, indicating wide variability in potential absenteeism rates in different settings.
We examined the sensitivity of the results to pandemic frequency by calculating costs and cost effectiveness assuming average time between pandemics ranging from 10 to 100 years (see Figure 6).
Estimates of the impact of a potential influenza pandemic range from 2 to 7.4 million deaths globally.
Of the twentieth century pandemics, the 1918 pandemic was the most severe with estimated attack rates for the full pandemic period ranging from 20 60% and estimated case fatality ratios ranging from 2 3% [10], [11].
In this exciting story of the 1918 pandemic, Barry ranges widely from medical facts and figures (between 50 million and 100 million dead worldwide) to the physiology of viruses to the development of the American Red Cross.
In the globular head region of the HA, the most varying part of the molecule, homology at the amino acid level between the Finnish pandemic strains ranged from 98.3% to 100%.
Because the risk for severe outcomes and differences in the rates of transmission of the virus can vary, the effects on the population observed during pandemics have ranged from those similar to severe seasonal influenza epidemics to those experienced during the 1918 influenza pandemic.
The last four influenza pandemics have ranged in severity from mild, having an estimated case fatality ratio (CFR) between 0.01% and 0.08% [ 1] as in the case of the 2009 pandemic, to severe, having an estimated case fatality ratio between 0.74% and 1.8% [ 2- 4] as in the case of the 1918 pandemic.
