Figure 1. Heterogeneity in infectiousness for a range of diseases.
The measure used is the 20/XX index, which quantifies the proportion of the transmission (XX%) that results from the most infectious 20% of the population. Confidence intervals are included where available. The interval for tick-borne encephalitis (Italy)21 indicates possible values depending on assumptions made about host susceptibility. STDs, sexually transmitted diseases; HIV, human immunodeficiency virus; AIDS, acquired immunodeficiency syndrome; SARS, severe acute respiratory syndrome.