Volume 14, Number 1—January 2008
Dispatch
Adamantane-Resistant Influenza Infection During the 2004–05 Season
Mahbubur Rahman*1, Rick A. Bright†2, Burney A. Kieke*, James G. Donahue*, Robert T. Greenlee*, Mary Vandermause*, Amanda Balish†, Angela Foust†, Nancy J. Cox†, Alexander I. Klimov†, David K. Shay†, and Edward A. Belongia*
Table 2
Demographic features of patients with adamantine-resistant or -susceptible influenza A, 2004–05 season*
| Variable | No. (%) resistant isolates, n = 72 | No. (%) susceptible isolates, n = 80 | Unadjusted prevalence ratio (95% CI) | Adjusted prevalence ratio (95% CI) |
|---|---|---|---|---|
| Age and high-risk status† | ||||
| 6–23 mo without high risk | 20 (74.1) | 7 (25.9) | 2.0 (1.3–3.0) | 2.1 (1.4–3.1) |
| 6–23 mo with high risk | 3 (50.0) | 3 (50.0) | 1.3 (0.6–3.2) | 1.4 (0.5–3.5) |
| 2–17 y with high risk | 8 (61.5) | 5 (38.5) | 1.7 (0.9–2.9) | 1.4 (0.8–2.4) |
| 18–49 y with high risk | 7 (36.8) | 12 (63.2) | 1.0 (0.5–2.0) | 0.9 (0.5–1.9) |
| 50–64 y with high risk | 8 (38.1) | 13 (61.9) | 1.0 (0.5–2.0) | 1.0 (0.6–1.9) |
| >65 y without high risk | 7 (46.7) | 8 (53.3) | 1.3 (0.7–2.4) | 1.2 (0.7–2.3) |
| >65 y with high risk | 19 (37.2) | 32 (62.8) | Referent group | Referent group |
| Sex | ||||
| Male | 37 (50.7) | 36 (49.3) | 1.1 (0.8–1.6) | 1.1 (0.8–1.5) |
| Female | 35 (44.3) | 44 (55.7) | Referent group | Referent group |
| Dates of clinical encounter | ||||
| 2005 Jan 3–23 | 10 (47.6) | 11 (52.4) | 0.9 (0.5–1.4) | 0.9 (0.5–1.5) |
| 2005 Jan 24–Feb 13 | 44 (55.0) | 36 (45.0) | Referent period | Referent period |
| 2005 Feb 14–Mar 6 | 15 (35.7) | 27 (64.3) | 0.6 (0.4–1.0) | 0.6 (0.4–1.0) |
| 2005 Mar 7–25 | 3 (33.3) | 6 (66.7) | 0.6 (0.2–1.6) | 0.5 (0.2–1.3) |
| Received 2004–05 influenza vaccine? | ||||
| Yes | 45 (42.9) | 60 (57.1) | 0.7 (0.5–1.0) | 0.8 (0.6–1.1) |
| No | 27 (57.4) | 20 (42.6) | Referent group | Referent group |
*CI, confidence interval.
†For the multivariate model, a composite variable was created based on age and the presence or absence of a high-risk medical condition as defined by Advisory Committee on Immunization Practices criteria.
