Case, Death, and Vaccination Trends 
Infections spread from one susceptible individual to another, a chain of exposures or contacts – it is the basis for track and trace.
R0 – How infectious is the virus?
Our current vaccination rate is around 38%, despite a flu season last year that took 80,000 lives.
By Rebecca Chisholm, University of Melbourne and
Death knells are beginning to ring for poliovirus. The CDC reports that, in 2014, there were 359 new cases of wild poliovirus in nine countries.