From: Quantifying the annual incidence and underestimation of seasonal influenza: A modelling approach
Seasonal influenza in the US: 2011-2012 and 2012-2013 influenza seasons | ||
Laboratory-confirmed infections* | 27,012 | 75,772 |
Estimates generated from Modified CDC-defined ILI in RCT | ||
Season | 2011-12 | 2012-13 |
Percent of influenza cases captured in surveillance | 0.5% (0.41−0.61%) | 0.27% (0.2−0.33%) |
Expansion factor | 200.1 (163.4−243.9) | 376.1 (306.7−455.1) |
Estimated symptomatic influenza illnesses | 5.4×106 (4.4×106−6.9×106) | 2.9×107 (2.3×107−3.4×107) |
Basic reproduction number | 1.19 (1.19−1.19) | 1.16 (1.16−1.16) |
Estimates generated from respiratory illness associated influenza in RCT | ||
Season | 2011-12 | 2012-13 |
Percent of influenza cases captured in surveillance | 0.1% (0.08−0.12%) | 0.09% (0.07−0.11%) |
Expansion factor | 1030.1 (840.5−1247.0) | 1111.4 (906.6−1345.3) |
Estimated symptomatic influenza illnesses | 2.8×107 (2.3×107−3.4×107) | 8.4×107 (6.9×107−1.02×108) |
Basic reproduction number | 1.20 (1.20−1.20) | 1.19 (1.19−1.19) |
US CDC estimated symptomatic influenza illnesses | 9.3×106 | 3.4×107 |