Multivariate Regression Analysis of the Impact of Various Factors on Antibody Concentrations and Expected Infant Seropositivity Rates
| Determinants . | Anti-PT GMC . | Anti-FHA GMC . | Infant Seropositivitya . | ||||
|---|---|---|---|---|---|---|---|
| . | No. (%) . | Ratio (95% CI) . | P Value . | Ratio (95% CI) . | P Value . | OR (95% CI) . | P Value . |
| Gestational week at maternal Tdap immunization | |||||||
| 39–41 | 21 (6) | Reference category | |||||
| 37–38 | 74 (22) | 3.8 (2.2–6.7) | <.001*** | 4.2 (2.5–7.1) | <.001*** | 6.9 (2.0–23.2) | .002** |
| 34–36 | 72 (22) | 5.7 (3.2–10.1) | <.001*** | 8.8 (5.2–15.1) | <.001*** | 10.9 (3.1–38.0) | <.001*** |
| 30–33 | 16 (5) | 9.9 (4.7–20.9) | <.001*** | 15.7 (7.8–31.6) | <.001*** | 17.3 (3.4–86.9) | .001** |
| 26–29 | 30 (9) | 11.3 (5.9–21.9) | <.001*** | 18.4 (10.0–34.0) | <.001*** | 27.4 (6.4–116.9) | <.001*** |
| 22–25 | 54 (16) | 10.0 (5.5–18.0) | <.001*** | 13.2 (7.6–22.9) | <.001*** | 43.2 (10.8–173.1) | <.001*** |
| 17–21 | 42 (13) | 8.7 (4.7–16.3) | <.001*** | 14.8 (8.2–26.5) | <.001*** | 27.5 (6.9–110.7) | <.001*** |
| 13–16 | 26 (8) | 7.7 (3.9–15.1) | <.001*** | 16.3 (8.7–30.5) | <.001*** | 32.4 (7.2–145.7) | <.001*** |
| Gestational age at birth (per week) | 335 (100) | 1.4 (1.3–1.5) | <.001*** | 1.5 (1.3–1.6) | <.001*** | 1.7 (1.3–2.1) | <.001*** |
| Maternal age (per 5 y) | 335 (100) | 0.9 (.8–.99) | .028* | 0.96 (.85–1.1) | .506 | 0.8 (.7–1.1) | .187 |
| Parity | |||||||
| Primiparous | 178 (53) | Reference category | |||||
| Multiparous | 157 (47) | 1.2 (.9–1.5) | .281 | 1.0 (.8–1.3) | .955 | 1.0 (.7–1.1) | .944 |
| Professional contact with children | 36 (11) | 0.7 (.5–1.1) | .113 | 0.8 (.5–1.2) | .234 | 0.7 (.3–1.5) | .319 |
| SES score | 0.99 (.95–1.0) | .667 | 1.0 (.95–1.0) | .671 | 1.0 (.9–1.1) | .869 | |
| Determinants . | Anti-PT GMC . | Anti-FHA GMC . | Infant Seropositivitya . | ||||
|---|---|---|---|---|---|---|---|
| . | No. (%) . | Ratio (95% CI) . | P Value . | Ratio (95% CI) . | P Value . | OR (95% CI) . | P Value . |
| Gestational week at maternal Tdap immunization | |||||||
| 39–41 | 21 (6) | Reference category | |||||
| 37–38 | 74 (22) | 3.8 (2.2–6.7) | <.001*** | 4.2 (2.5–7.1) | <.001*** | 6.9 (2.0–23.2) | .002** |
| 34–36 | 72 (22) | 5.7 (3.2–10.1) | <.001*** | 8.8 (5.2–15.1) | <.001*** | 10.9 (3.1–38.0) | <.001*** |
| 30–33 | 16 (5) | 9.9 (4.7–20.9) | <.001*** | 15.7 (7.8–31.6) | <.001*** | 17.3 (3.4–86.9) | .001** |
| 26–29 | 30 (9) | 11.3 (5.9–21.9) | <.001*** | 18.4 (10.0–34.0) | <.001*** | 27.4 (6.4–116.9) | <.001*** |
| 22–25 | 54 (16) | 10.0 (5.5–18.0) | <.001*** | 13.2 (7.6–22.9) | <.001*** | 43.2 (10.8–173.1) | <.001*** |
| 17–21 | 42 (13) | 8.7 (4.7–16.3) | <.001*** | 14.8 (8.2–26.5) | <.001*** | 27.5 (6.9–110.7) | <.001*** |
| 13–16 | 26 (8) | 7.7 (3.9–15.1) | <.001*** | 16.3 (8.7–30.5) | <.001*** | 32.4 (7.2–145.7) | <.001*** |
| Gestational age at birth (per week) | 335 (100) | 1.4 (1.3–1.5) | <.001*** | 1.5 (1.3–1.6) | <.001*** | 1.7 (1.3–2.1) | <.001*** |
| Maternal age (per 5 y) | 335 (100) | 0.9 (.8–.99) | .028* | 0.96 (.85–1.1) | .506 | 0.8 (.7–1.1) | .187 |
| Parity | |||||||
| Primiparous | 178 (53) | Reference category | |||||
| Multiparous | 157 (47) | 1.2 (.9–1.5) | .281 | 1.0 (.8–1.3) | .955 | 1.0 (.7–1.1) | .944 |
| Professional contact with children | 36 (11) | 0.7 (.5–1.1) | .113 | 0.8 (.5–1.2) | .234 | 0.7 (.3–1.5) | .319 |
| SES score | 0.99 (.95–1.0) | .667 | 1.0 (.95–1.0) | .671 | 1.0 (.9–1.1) | .869 | |
Abbreviations: CI, confidence interval; EU, enzyme-linked immunosorbent assay units; FHA, filamentous hemagglutinin; GMC, geometric mean concentration; OR, odds ratio; PT, pertussis toxin; SES, socioeconomic status [24]; Tdap, tetanus-diphtheria-acellular pertussis.
a Infant seropositivity defined as birth anti-PT >30 EU/mL.
*P < .05, **P < .01, ***P < .001.
Multivariate Regression Analysis of the Impact of Various Factors on Antibody Concentrations and Expected Infant Seropositivity Rates
| Determinants . | Anti-PT GMC . | Anti-FHA GMC . | Infant Seropositivitya . | ||||
|---|---|---|---|---|---|---|---|
| . | No. (%) . | Ratio (95% CI) . | P Value . | Ratio (95% CI) . | P Value . | OR (95% CI) . | P Value . |
| Gestational week at maternal Tdap immunization | |||||||
| 39–41 | 21 (6) | Reference category | |||||
| 37–38 | 74 (22) | 3.8 (2.2–6.7) | <.001*** | 4.2 (2.5–7.1) | <.001*** | 6.9 (2.0–23.2) | .002** |
| 34–36 | 72 (22) | 5.7 (3.2–10.1) | <.001*** | 8.8 (5.2–15.1) | <.001*** | 10.9 (3.1–38.0) | <.001*** |
| 30–33 | 16 (5) | 9.9 (4.7–20.9) | <.001*** | 15.7 (7.8–31.6) | <.001*** | 17.3 (3.4–86.9) | .001** |
| 26–29 | 30 (9) | 11.3 (5.9–21.9) | <.001*** | 18.4 (10.0–34.0) | <.001*** | 27.4 (6.4–116.9) | <.001*** |
| 22–25 | 54 (16) | 10.0 (5.5–18.0) | <.001*** | 13.2 (7.6–22.9) | <.001*** | 43.2 (10.8–173.1) | <.001*** |
| 17–21 | 42 (13) | 8.7 (4.7–16.3) | <.001*** | 14.8 (8.2–26.5) | <.001*** | 27.5 (6.9–110.7) | <.001*** |
| 13–16 | 26 (8) | 7.7 (3.9–15.1) | <.001*** | 16.3 (8.7–30.5) | <.001*** | 32.4 (7.2–145.7) | <.001*** |
| Gestational age at birth (per week) | 335 (100) | 1.4 (1.3–1.5) | <.001*** | 1.5 (1.3–1.6) | <.001*** | 1.7 (1.3–2.1) | <.001*** |
| Maternal age (per 5 y) | 335 (100) | 0.9 (.8–.99) | .028* | 0.96 (.85–1.1) | .506 | 0.8 (.7–1.1) | .187 |
| Parity | |||||||
| Primiparous | 178 (53) | Reference category | |||||
| Multiparous | 157 (47) | 1.2 (.9–1.5) | .281 | 1.0 (.8–1.3) | .955 | 1.0 (.7–1.1) | .944 |
| Professional contact with children | 36 (11) | 0.7 (.5–1.1) | .113 | 0.8 (.5–1.2) | .234 | 0.7 (.3–1.5) | .319 |
| SES score | 0.99 (.95–1.0) | .667 | 1.0 (.95–1.0) | .671 | 1.0 (.9–1.1) | .869 | |
| Determinants . | Anti-PT GMC . | Anti-FHA GMC . | Infant Seropositivitya . | ||||
|---|---|---|---|---|---|---|---|
| . | No. (%) . | Ratio (95% CI) . | P Value . | Ratio (95% CI) . | P Value . | OR (95% CI) . | P Value . |
| Gestational week at maternal Tdap immunization | |||||||
| 39–41 | 21 (6) | Reference category | |||||
| 37–38 | 74 (22) | 3.8 (2.2–6.7) | <.001*** | 4.2 (2.5–7.1) | <.001*** | 6.9 (2.0–23.2) | .002** |
| 34–36 | 72 (22) | 5.7 (3.2–10.1) | <.001*** | 8.8 (5.2–15.1) | <.001*** | 10.9 (3.1–38.0) | <.001*** |
| 30–33 | 16 (5) | 9.9 (4.7–20.9) | <.001*** | 15.7 (7.8–31.6) | <.001*** | 17.3 (3.4–86.9) | .001** |
| 26–29 | 30 (9) | 11.3 (5.9–21.9) | <.001*** | 18.4 (10.0–34.0) | <.001*** | 27.4 (6.4–116.9) | <.001*** |
| 22–25 | 54 (16) | 10.0 (5.5–18.0) | <.001*** | 13.2 (7.6–22.9) | <.001*** | 43.2 (10.8–173.1) | <.001*** |
| 17–21 | 42 (13) | 8.7 (4.7–16.3) | <.001*** | 14.8 (8.2–26.5) | <.001*** | 27.5 (6.9–110.7) | <.001*** |
| 13–16 | 26 (8) | 7.7 (3.9–15.1) | <.001*** | 16.3 (8.7–30.5) | <.001*** | 32.4 (7.2–145.7) | <.001*** |
| Gestational age at birth (per week) | 335 (100) | 1.4 (1.3–1.5) | <.001*** | 1.5 (1.3–1.6) | <.001*** | 1.7 (1.3–2.1) | <.001*** |
| Maternal age (per 5 y) | 335 (100) | 0.9 (.8–.99) | .028* | 0.96 (.85–1.1) | .506 | 0.8 (.7–1.1) | .187 |
| Parity | |||||||
| Primiparous | 178 (53) | Reference category | |||||
| Multiparous | 157 (47) | 1.2 (.9–1.5) | .281 | 1.0 (.8–1.3) | .955 | 1.0 (.7–1.1) | .944 |
| Professional contact with children | 36 (11) | 0.7 (.5–1.1) | .113 | 0.8 (.5–1.2) | .234 | 0.7 (.3–1.5) | .319 |
| SES score | 0.99 (.95–1.0) | .667 | 1.0 (.95–1.0) | .671 | 1.0 (.9–1.1) | .869 | |
Abbreviations: CI, confidence interval; EU, enzyme-linked immunosorbent assay units; FHA, filamentous hemagglutinin; GMC, geometric mean concentration; OR, odds ratio; PT, pertussis toxin; SES, socioeconomic status [24]; Tdap, tetanus-diphtheria-acellular pertussis.
a Infant seropositivity defined as birth anti-PT >30 EU/mL.
*P < .05, **P < .01, ***P < .001.
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