Table.
Rate of invasive pneumococcal disease per 100,000 child-years and univariate and multivariate Poisson regression analysis for risk factors of IPD
| Study Period | Disease Rate (No. cases) | Univariate analysis | Multivariate analysisa | ||
|---|---|---|---|---|---|
| Cumulative (Jan 1996–Dec 2005) | Pre-PCV7 (Jan 1996–Jun 2000) | Post-PCV7 (Jul 2001–Dec 2005) | RR (95%CI) | RR (95%CI) | |
| Years | |||||
| January 1996–June 2000b | 188.3 (228) | 188.3 (228) | -- | 1.00 | 1.00 |
| July 2000–June 2001 | 146.3 (89) | -- | -- | 0.78 (0.61–0.99) | 1.03 (0.80–1.32) |
| July 2001–December 2005 | 32.7 (88) | -- | 32.7 (88) | 0.17 (0.14–0.22) | 0.26 (0.20–0.34) |
| Age (months) | |||||
| 0–23b | 151.3 (339) | 236.5 (207) | 57.8 (62) | 1.00 | 1.00 |
| 24–59 | 41.9 (39) | 77.0 (17) | 20.3 (12) | 0.28 (0.20–0.39) | 0.28 (0.20–0.40) |
| 36–59 | 20.2 (27) | 34.8 (4) | 13.7 (14) | 0.13 (0.09–0.20) | 0.16 (0.11–0.24) |
| Sex | |||||
| Boyb | 110.8 (254) | 223.7 (138) | 41.8 (57) | 1.00 | 1.00 |
| Girl | 68.2 (151) | 151.5 (90) | 23.4 (31) | 0.61 (0.50–0.75) | 0.66 (0.54–0.80) |
| High-risk conditions | |||||
| Yesc | 201.1 (80) | 456.7 (39) | 103.4 (27) | 2.80 (2.18–3.61) | 4.01 (3.10–5.17) |
| Asthma only | 110.4 (87) | 282.8 (47) | 34.8 (18) | 1.54 (1.20–1.97) | 2.09 (1.63–2.69) |
| Nob | 71.7 (238) | 148.0 (142) | 22.5 (43) | 1.00 | 1.00 |
| Race/ethnicity and hemoglobin type | |||||
| White normal hemoglobinb | 80.9 (112) | 174.4 (64) | 30.1 (25) | 1.00 | 1.00 |
| Black hemoglobin S or C trait | 139.8 (38) | 260.8 (21) | 46.0 (7) | 1.73 (1.20–2.50) | 1.77 (1.22–2.55) |
| Hemoglobin S traitd | 142.6 (30) | 300.9 (19) | 25.6 (3) | −1.76 (1.18–2.64) | −1.80 (1.20–2.69) |
| Hemoglobin C traitd | 130.1 (8) | 115.0 (2) | 113.7 (4) | −1.61 (0.78–3.29) | −1.66 (0.81–3.39) |
| Black normal hemoglobin | 95.6 (244) | 190.6 (138) | 34.6 (51) | 1.18 (0.95–1.48) | 1.25 (1.00–1.56) |
| Hispanic normal hemoglobin | 36.7 (11) | 126.2 (5) | 21.7 (5) | 0.45 (0.24–0.84) | 0.61 (0.33–1.14) |
The original multivariate model reported here includes variables (categorical) for study years, ages, gender, high risk conditions and four race-ethnicity hemoglobin groups: one combined risk group for hemoglobin S or C trait (blacks only) and three separate groups for normal hemoglobin (blacks, Hispanics and whites as reference).
Reference category.
High-risk conditions include HIV, cancer or immunosuppression, sickle cell disease, congenital heart disease, diabetes mellitus, renal disease, hepatic disease and chronic lung disease.
The subgroup-specific risk ratios for hemoglobin S trait and hemoglobin C trait are reported from an identical (secondary) multivariate model, except without trait risk groups S and C combined.