Table 4.
Estimated Influenza Type- or Subtype-Specific Hospitalization Rates by Negative Binomial Regression Models
| Aged <1 y | Aged 1–4 y | Aged 5–49 y | Aged 50–64 y | Aged ≥65 y | All Agesa | |||||||||||||
| Season | A(H1) | A(H3) | B | A(H1) | A(H3) | B | A(H1) | A(H3) | B | A(H1) | A(H3) | B | A(H1) | A(H3) | B | A(H1) | A(H3) | B |
| 1993–1994b | 0.8 | 91.6 | 0.0 | 0.1 | 14.6 | 0.1 | 0.0 | 12.0 | 0.1 | 0.0 | 55.3 | 0.3 | 0.0 | 234.1 | 0.8 | 0.0 | 47.3 | 0.2 |
| 1994–1995b | 8.1 | 34.1 | 7.4 | 0.4 | 3.0 | 13.4 | 0.2 | 5.5 | 6.8 | 0.1 | 32.4 | 17.3 | 0.2 | 145.0 | 57.8 | 0.3 | 27.1 | 15.0 |
| 1995–1996 | 135.8 | 48.6 | 6.8 | 8.4 | 5.1 | 10.1 | 3.3 | 5.1 | 5.2 | 4.4 | 26.5 | 11.9 | 6.5 | 124.2 | 36.0 | 6.0 | 23.7 | 10.3 |
| 1996–1997b | 0.0 | 66.9 | 26.5 | 0.0 | 6.1 | 32.3 | 0.0 | 8.7 | 12.1 | 0.0 | 52.0 | 32.3 | 0.0 | 258.0 | 111.8 | 0.0 | 46.8 | 28.8 |
| 1997–1998b | 1.5 | 126.6 | 0.0 | 0.1 | 23.1 | 0.5 | 0.0 | 13.4 | 0.3 | 0.0 | 75.2 | 0.6 | 0.1 | 384.4 | 2.2 | 0.1 | 70.9 | 0.6 |
| 1998–1999b | 1.2 | 96.4 | 25.0 | 0.1 | 8.7 | 26.0 | 0.0 | 9.3 | 10.3 | 0.0 | 59.0 | 26.3 | 0.0 | 307.9 | 90.0 | 0.0 | 55.0 | 23.7 |
| 1999–2000b | 16.6 | 102.3 | 0.0 | 1.2 | 20.5 | 1.7 | 0.3 | 14.3 | 0.5 | 0.2 | 77.6 | 1.2 | 0.4 | 391.9 | 4.5 | 0.6 | 72.2 | 1.2 |
| 2000–2001 | 126.3 | 1.2 | 19.8 | 7.1 | 0.1 | 39.1 | 2.5 | 0.2 | 15.4 | 3.3 | 1.0 | 40.1 | 7.0 | 6.1 | 149.0 | 5.1 | 1.0 | 37.0 |
| 2001–2002b | 8.2 | 112.0 | 10.7 | 0.4 | 12.4 | 26.3 | 0.1 | 9.5 | 7.1 | 0.1 | 57.3 | 17.9 | 0.6 | 317.7 | 69.9 | 0.3 | 56.6 | 17.6 |
| 2002–2003 | 132.0 | 15.5 | 16.4 | 10.6 | 2.2 | 28.1 | 3.1 | 2.0 | 11.0 | 3.1 | 11.9 | 26.9 | 6.3 | 65.5 | 94.0 | 5.7 | 11.6 | 24.7 |
| 2003–2004b | 0.0 | 318.0 | 0.0 | 0.0 | 89.4 | 2.1 | 0.0 | 20.7 | 0.5 | 0.0 | 91.2 | 1.1 | 0.0 | 503.7 | 4.8 | 0.0 | 99.0 | 1.2 |
| 2004–2005b | 0.0 | 108.2 | 31.8 | 0.0 | 8.7 | 43.4 | 0.0 | 9.6 | 12.9 | 0.0 | 56.9 | 32.8 | 0.0 | 319.6 | 133.2 | 0.0 | 56.5 | 32.7 |
| 2005–2006b | 10.7 | 151.2 | 14.1 | 0.3 | 13.1 | 28.8 | 0.2 | 8.4 | 7.0 | 0.0 | 42.5 | 16.6 | 0.7 | 237.0 | 64.5 | 0.3 | 44.1 | 16.9 |
| 2006–2007 | 124.6 | 33.1 | 6.9 | 10.7 | 5.0 | 17.6 | 2.2 | 3.3 | 5.3 | 2.3 | 16.8 | 11.6 | 5.7 | 91.4 | 42.0 | 4.8 | 16.7 | 11.5 |
| 2007–2008b | 156.7 | 50.9 | 29.2 | 10.1 | 5.8 | 48.7 | 2.4 | 6.4 | 16.2 | 1.5 | 39.1 | 40.9 | 3.2 | 212.2 | 165.5 | 4.9 | 37.5 | 40.4 |
| Minimum | 0.0 | 1.2 | 0.0 | 0.0 | 0.1 | 0.1 | 0.0 | 0.2 | 0.1 | 0.0 | 1.0 | 0.3 | 0.0 | 6.1 | 0.8 | 0.0 | 1.0 | 0.2 |
| Maximum | 156.7 | 318.0 | 31.8 | 10.7 | 89.4 | 48.7 | 3.3 | 20.7 | 16.2 | 4.4 | 91.2 | 40.9 | 7.0 | 503.7 | 165.5 | 6.4 | 99.0 | 40.4 |
| Mean | 48.2 | 90.4 | 13.0 | 3.3 | 14.5 | 21.2 | 1.0 | 8.6 | 7.4 | 1.0 | 46.3 | 18.5 | 2.1 | 239.9 | 68.4 | 1.9 | 44.4 | 17.5 |
| 95% CI | 32.6–232.6 | 70.2–225.0 | 2.9–203.8 | 0.0–66.3 | 8.0– | 15.6–79.7 | 0.2–15.6 | 5.0–21.6 | 4.6–21.4 | 0.0–70.8 | 28.5–111.8 | 6.6–88.4 | 0.0–268.0 | 164.0–485.5 | 22.6–344.6 | 0.6–60.9 | 29.3–98.1 | 7.7–77.3 |
Abbreviation: CI, confidence interval.
Data are hospitalization rates per 100 000 person-years and represent summaries from 13 state-based model estimates.
a
Standardized with 2000 census population figures for each age group.
b
Seasons in which ≥50% of all infection isolates were subtyped as influenza A(H3N2).