Table 1.
Participant Characteristics
| Age Group | Overall | 50–59 | 60–69 | 70–79 | 80+ |
|---|---|---|---|---|---|
| Subject no. | 90 | 26 | 23 | 27 | 14 |
| Sex (%) | |||||
| Male | 44.4 | 23.1 | 52.2 | 55.6 | 50.0 |
| Female | 55.6 | 76.9 | 47.8 | 44.4 | 50.0 |
| Race (%) | |||||
| White | 94.4 | 84.6 | 95.7 | 100.0 | 100.0 |
| Black | 4.4 | 11.5 | 4.3 | 0.0 | 0.0 |
| Other | 1.1 | 3.8 | 0.0 | 0.0 | 0.0 |
| Comorbiditya (%) | |||||
| Heart | 1.1 | 3.8 | 17.4 | 7.4 | 0.0 |
| Lung | 7.8 | 19.2 | 4.3 | 7.4 | 7.1 |
| Immune | 10.0 | 0.0 | 0.0 | 7.4 | 7.1 |
| HI ≥40 (%) | |||||
| H1N1 | |||||
| Day 0 | 10.2 | 8.0 | 13.0 | 7.7 | 14.3 |
| Day 28 | 33.7 | 40.7 | 39.1 | 28.0 | 21.4 |
| H3N2 | |||||
| Day 0 | 29.5 | 32.0 | 30.4 | 26.9 | 28.6 |
| Day 28 | 77.5 | 74.1 | 82.6 | 92.0 | 50.0 |
| ≥4-fold rise (%) | |||||
| H1N1 | 22.7 | 20.0 | 17.4 | 26.9 | 28.6 |
| H3N2 | 64.8 | 72.0 | 47.8 | 76.9 | 57.1 |
Abbreviations: HI, hemagglutination inhibition; HIV, human immunodeficiency virus.
a Comorbid conditions include heart and lung disease, and immunosuppression (Immune). Immunosuppression includes immune dysfunction (including HIV), transplant, chemotherapy, steroid, or other immune-modulating medications.