Table 2.
Week numbers with corresponding dates of first events and highest event rates for patients with influenza hospitalized at a network of three tertiary care hospitals during the 2013–2014 influenza season*
| Event | Hospital A |
Hospital B |
Hospital C |
|||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Week of first event (date) | Highest weekly rate | Week of highest rate (date) | Week of first event (date) | Highest weekly rate | Week of highest rate (date) | Week of first event (date) | Highest weekly rate | Week of highest rate (date) | ||
| Hospitalization† | 39.0 | 1 (12/29) | 24.5 | 4 (1/19) | 26.4 | 4 (1/19) | ||||
| Positive PCR | 46 (11/10) | 49 (12/1) | 42 (10/13) |
|||||||
| ICD-9 code | 43 (10/20) | 39 (9/22) | 50 (12/8) | |||||||
| ICU‡ | 45 (11/3) | 19.5 | 1 (12/29) | 50 (12/8) | 9.1 | 7 (2/9) | 42 (10/13) |
15.2 | 4 (1/19) | |
| Mechanical ventilation‡ | 46 (11/10) | 15.4 | 1 (12/29) | 50 (12/8) | 6.7 | 7 (2/9) | 43 (10/20) | 13.0 | 5 (1/26) | |
| ECMO‡ | 50 (12/8) | 3.7 | 1 (12/29) | 2 (1/5) | 3.1 | 11 (3/9) | 5 (1/26) | 1.2 | 7 (2/9) | |
| Death§ | 45 (11/3) | 0.2 | 1 (12/29) | 3 (1/12) | 0.2 | 13 (3/23) | 45 (11/3) | 0.7 | 1 (12/29) | |
Definition of abbreviations: ECMO = extracorporeal membrane oxygenation; ICD-9 = International Classification of Diseases, 9th Revision; ICU = intensive care unit; PCR = polymerase chain reaction.
Dates are given as Morbidity and Mortality Weekly Report (MMWR) week numbers and corresponding week start dates (15). Weeks 32–52 correspond to the last 21 weeks of 2013, and Weeks 1–15 correspond to the first 15 weeks of 2014.
Rates of hospitalization are given as hospitalizations of patients with influenza per week per 1,000 total admissions.
Rates of ICU, mechanical ventilation, and ECMO use are given as days of utilization per week per 1,000 total patient-days (influenza and noninfluenza patient-days).
Death rates are given as deaths per week per 1,000 total patient-days.