Tdap vaccination during pregnancy, by sociodemographic and pregnancy characteristics
| Characteristic | All births, no. (%)* | No. vaccinated | Vaccine coverage, % (95% CI) | Unadjusted rate ratio (95% CI) | Adjusted rate ratio (95% CI)† |
|---|---|---|---|---|---|
| Overall | 991 850 (100.0) | 69 303 | 7.0 (6.9–7.0) | – | – |
| Maternal age, yr | |||||
| < 20 | 19 628 (2.0) | 622 | 3.2 (2.9–3.4) | 0.41 (0.38–0.44) | 0.58 (0.53–0.62) |
| 20–24 | 99 218 (10.0) | 4298 | 4.3 (4.2–4.5) | 0.56 (0.54–0.58) | 0.69 (0.67–0.71) |
| 25–29 | 262 061 (26.4) | 17 283 | 6.6 (6.5–6.7) | 0.86 (0.84–0.87) | 0.91 (0.90–0.93) |
| 30–34 | 369 744 (37.3) | 28 518 | 7.7 (7.6–7.8) | 1.00 (Ref.) | 1.00 (Ref.) |
| ≥ 35 | 241 199 (24.3) | 18 582 | 7.7 (7.6–7.8) | 1.00 (0.98–1.02) | 1.01 (0.99–1.02) |
| Fiscal year of conception‡ | |||||
| 2011/12 | 95 494 (9.6) | 385 | 0.4 (0.4–0.4) | 0.097 (0.088–0.11) | 0.099 (0.089–0.11) |
| 2012/13 | 124 712 (12.6) | 1323 | 1.1 (1.0–1.1) | 0.26 (0.24–0.27) | 0.26 (0.34–0.27) |
| 2013/14 | 124 978 (12.6) | 2043 | 1.6 (1.6–1.7) | 0.39 (0.37–0.41) | 0.39 (0.37–0.41) |
| 2014/15 | 124 155 (12.5) | 2426 | 2.0 (1.9–2.0) | 0.47 (0.45–0.49) | 0.47 (0.44–0.49) |
| 2015/16 | 124 215 (12.5) | 4478 | 3.6 (3.5–3.7) | 0.87 (0.84–0.90) | 0.86 (0.83–0.89) |
| 2016/17 | 123 417 (12.4) | 5122 | 4.2 (4.0–4.3) | 1.00 (Ref.) | 1.00 (Ref.) |
| 2017/18 | 122 830 (12.4) | 14 431 | 11.7 (11.6–11.9) | 2.83 (2.74–2.92) | 1.41 (1.34–1.48) |
| 2018/19 | 122 322 (12.3) | 30 400 | 24.9 (24.6–25.1) | 5.99 (5.82–6.16) | 2.37 (2.25–2.49) |
| 2019/20 | 29 727 (3.0) | 8695 | 29.2 (28.7–29.8) | 7.05 (6.83–7.28) | 2.74 (2.60–2.89) |
| Parity | |||||
| 0 (nulliparous) | 433 315 (43.7) | 35 637 | 8.2 (8.1–8.3) | 1.36 (1.34–1.38) | 1.38 (1.36–1.40) |
| ≥ 1 (multiparous) | 558 535 (56.3) | 33 666 | 6.0 (6.0–6.1) | 1.00 (Ref.) | 1.00 (Ref.) |
| Multiple birth | |||||
| No | 973 589 (98.2) | 68 364 | 7.0 (7.0–7.1) | 1.00 (Ref.) | 1.00 (Ref.) |
| Yes | 18 261 (1.8) | 939 | 5.1 (4.8–5.5) | 0.73 (0.69–0.78) | 0.77 (0.73–0.82) |
| Pre-existing maternal medical condition§ | |||||
| Asthma | 2138 (0.2) | 127 | 5.9 (5.0–7.0) | 0.85 (0.72–1.01) | – |
| Chronic hypertension | 3947 (0.4) | 283 | 7.2 (6.4–8.0) | 1.03 (0.92–1.15) | – |
| Diabetes | 8702 (0.9) | 417 | 4.8 (4.4–5.3) | 0.68 (0.62–0.75) | – |
| Heart disease | 4806 (0.5) | 294 | 6.1 (5.5–6.8) | 0.87 (0.78–0.98) | – |
| Thyroid disease | 13 389 (1.3) | 1466 | 10.9 (10.4–11.5) | 1.58 (1.50–1.66) | – |
| Any pre-existing maternal medical condition† | |||||
| No | 960 721(96.9) | 66 825 | 7.0 (6.9–7.0) | 1.00 (Ref.) | 1.00 (Ref.) |
| Yes | 31 129 (3.1) | 2478 | 8.0 (7.7–8.3) | 1.14 (1.10–1.19) | 0.96 (0.93–1.00) |
| Neighbourhood median family income quintile | |||||
| 1 (lowest) | 210 933 (21.3) | 12 713 | 6.0 (5.9–6.1) | 0.76 (0.74–0.77) | 1.04 (1.01–1.08) |
| 2 | 199 725 (20.1) | 13 890 | 7.0 (6.8–7.1) | 0.87 (0.85–0.89) | 1.05 (1.02–1.08) |
| 3 | 207 562 (20.9) | 14 430 | 7.0 (6.8–7.1) | 0.87 (0.85–0.89) | 0.96 (0.93–0.98) |
| 4 | 208 050 (21.0) | 15 080 | 7.2 (7.1–7.4) | 0.91 (0.89–0.93) | 0.97 (0.95–0.99) |
| 5 (highest) | 165 580 (16.7) | 13 190 | 8.0 (7.8–8.1) | 1.00 (Ref.) | 1.00 (Ref.) |
| Rural residence | |||||
| No | 899 428 (90.7) | 63 968 | 7.1 (7.1–7.2) | 1.00 (Ref.) | 1.00 (Ref.) |
| Yes | 92 422 (9.3) | 5335 | 5.8 (5.6–5.9) | 0.81 (0.79–0.83) | 0.91 (0.88–0.93) |
| LHIN group¶ | |||||
| Central | 329 495 (33.2) | 23 010 | 7.0 (6.9–7.1) | 0.81 (0.79–0.83) | 0.91 (0.89–0.93) |
| East | 239 495 (24.2) | 19 784 | 8.3 (8.2–8.4) | 0.96 (0.93–0.98) | 1.07 (1.04–1.09) |
| North | 50 815 (5.1) | 1853 | 3.6 (3.5–3.8) | 0.42 (0.40–0.44) | 0.58 (0.55–0.61) |
| Toronto | 92 261 (9.3) | 7964 | 8.6 (8.5–8.8) | 1.00 (Ref.) | 1.00 (Ref.) |
| West | 279 784 (28.2) | 16 692 | 6.0 (5.9–6.1) | 0.69 (0.67–0.71) | 0.84 (0.82–0.86) |
| Marginalization indices** | |||||
| Residential instability quintile | |||||
| 1 (least marginalized) | 216 203 (21.8) | 14 721 | 6.8 (6.7–6.9) | 1.00 (Ref.) | 1.00 (Ref.) |
| 2 | 184 203 (18.6) | 13 131 | 7.1 (7.0–7.2) | 1.05 (1.02–1.07) | 1.02 (1.00–1.04) |
| 3 | 180 923 (18.2) | 12 764 | 7.1 (6.9–7.2) | 1.04 (1.01–1.06) | 1.02 (0.99–1.04) |
| 4 | 186 076 (18.8) | 12 270 | 6.6 (6.5–6.7) | 0.97 (0.95–0.99) | 1.03 (1.01–1.06) |
| 5 (most marginalized) | 224 445 (22.6) | 16 417 | 7.3 (7.2–7.4) | 1.07 (1.05–1.10) | 1.04 (1.01–1.07) |
| Material deprivation quintile | |||||
| 1 (least marginalized) | 201 373 (20.3) | 18 272 | 9.1 (8.9–9.2) | 1.00 (Ref.) | 1.00 (Ref.) |
| 2 | 196 248 (19.8) | 14 869 | 7.6 (7.5–7.7) | 0.84 (0.82–0.85) | 0.93 (0.91–0.94) |
| 3 | 187 025 (18.9) | 12 578 | 6.7 (6.6–6.8) | 0.74 (0.73–0.76) | 0.85 (0.83–0.87) |
| 4 | 186 870 (18.8) | 11,977 | 6.4 (6.3–6.5) | 0.71 (0.69–0.72) | 0.80 (0.78–0.83) |
| 5 (most marginalized) | 220 334 (22.2) | 11,607 | 5.3 (5.2–5.4) | 0.58 (0.57–0.59) | 0.69 (0.67–0.71) |
| Dependency quintile | |||||
| 1 (least marginalized) | 335 957 (33.9) | 24 105 | 7.2 (7.1–7.3) | 1.00 (Ref.) | 1.00 (Ref.) |
| 2 | 209 933 (21.2) | 14 932 | 7.1 (7.0–7.2) | 0.99 (0.97–1.01) | 1.06 (1.04–1.07) |
| 3 | 167 423 (16.9) | 11 454 | 6.8 (6.7–7.0) | 0.95 (0.93–0.97) | 1.05 (1.03–1.08) |
| 4 | 149 441 (15.1) | 10 371 | 6.9 (6.8–7.1) | 0.97 (0.95–0.99) | 1.08 (1.06–1.11) |
| 5 (most marginalized) | 129 096 (13.0) | 8441 | 6.5 (6.4–6.7) | 0.91 (0.89–0.93) | 1.03 (1.01–1.06) |
| Ethnic concentration quintile | |||||
| 1 (least marginalized) | 131 891 (13.3) | 7761 | 5.9 (5.8–6.0) | 1.00 (Ref.) | 1.00 (Ref.) |
| 2 | 150 188 (15.1) | 10 103 | 6.7 (6.6–6.9) | 1.14 (1.11–1.18) | 1.06 (1.03–1.09) |
| 3 | 169 086 (17.0) | 12 385 | 7.3 (7.2–7.4) | 1.24 (1.21–1.28) | 1.10 (1.07–1.13) |
| 4 | 210 064 (21.2) | 15 860 | 7.6 (7.4–7.7) | 1.28 (1.25–1.32) | 1.13 (1.10–1.17) |
| 5 (most marginalized) | 330 621 (33.3) | 23 194 | 7.0 (6.9–7.1) | 1.19 (1.16–1.22) | 1.16 (1.13–1.20) |
| Prenatal care†† | |||||
| Intensive | 54 690 (5.5) | 4302 | 7.9 (7.6–8.1) | 0.96 (0.93–0.99) | 1.01 (0.99–1.04) |
| Adequate | 409 609 (41.3) | 33 468 | 8.2 (8.1–8.3) | 1.00 (Ref.) | 1.00 (Ref.) |
| Intermediate | 337 279 (34.0) | 21 379 | 6.3 (6.3–6.4) | 0.78 (0.76–0.79) | 0.88 (0.87–0.90) |
| Inadequate | 134 621 (13.6) | 7875 | 5.8 (5.7–6.0) | 0.72 (0.70–0.73) | 0.56 (0.55–0.57)§§ |
| No care or missing†,‡,§,¶,**,††,‡‡ | 55 651 (5.6) | 2279 | 4.1 (3.9–4.3) | 0.50 (0.48–0.52) | – |
| Composition of prenatal care visits | |||||
| No visits | 55 649 (5.6) | 2279 | 4.1 (3.9–4.3) | 0.68 (0.65–0.71) | 1.12 (1.07–1.17) |
| ≥ 75% with GP or FP | 141 591 (14.3) | 15 610 | 11.0 (10.9–11.2) | 1.82 (1.79–1.86) | 1.97 (1.94–2.01) |
| ≥ 75% with OBGYN | 606 758 (61.2) | 36 701 | 6.0 (6.0–6.1) | 1.00 (Ref.) | 1.00 (Ref.) |
| Mix of providers | 187 852 (18.9) | 14 713 | 7.8 (7.7–8.0) | 1.29 (1.27–1.32) | 1.31 (1.28–1.33) |
Note: CI = confidence interval, GP = general practitioner, FP = family physician, LHIN = Local Health Integration Network, OBGYN = obstetrician–gynecologist, REF = reference category, Tdap = tetanus toxoid, reduced diphtheria toxoid and acellular pertussis.
↵* Column percentages.
↵† The multivariable model included in all of the independent variables listed in this table, except a dichotomous variable for pre-existing medical conditions, was added instead of the individual conditions in this variable, and the category for inadequate prenatal care was combined with no care or missing prenatal care to allow for model convergence.
↵‡ A fiscal year begins on Apr. 1 and ends on Mar. 31. As the cohort was created using the delivery date on the maternal record (Apr. 1, 2012, to Mar. 31, 2020), fiscal years 2011/12 and 2019/20 are incomplete, which explains the lower number of births shown in these 2 fiscal years.
↵§ Sum of each individual condition does not equal number of pregnant people with any condition, as categories were not mutually exclusive.
↵¶ Local Health Integration Network groups were assigned according to the Ontario Ministry of Health (Appendix 1, eTable 2).
↵** Scores corresponding to each of these 4 dimensions were previously divided into quintiles, where quintile 1 represents the least marginalized areas, and quintile 5, the most marginalized areas. Please see Appendix 1, eTable 2 for complete descriptions of what is captured in each of these 4 dimensions.
↵†† Adequacy of prenatal care characterized using the Revised-Graduated Prenatal Care Utilization Index.
↵‡‡ Mother did not have any prenatal visits within our definition.
↵§§ Estimate is for inadequate and no care or missing prenatal care combined.