Table 1.
Characteristics of the Cohort by IIV Status during Pregnancy
| Total N | Vaccinated n=799 n (row %) |
Not Vaccinated n=426 n (row %) |
p-value | |
|---|---|---|---|---|
| Demographic Characteristics | ||||
| Maternal Race/Ethnicity | ||||
| Non-Hispanic White | 769 | 504 (65.5%) | 265 (34.5%) | <0.01 |
| Non-Hispanic Black | 40 | 17 (42.5%) | 23 (57.5%) | |
| Hispanic | 151 | 94 (62.3%) | 57 (37.8%) | |
| Asian | 165 | 120 (72.7%) | 45 (27.3%) | |
| Mixed/Other/Unknown | 100 | 64 (64.0%) | 36 (36.0%) | |
| Maternal Age (years) | ||||
| <30 | 418 | 249 (59.6%) | 169 (40.4%) | <0.01 |
| 30–34 | 498 | 349 (70.1%) | 149 (29.9%) | |
| 35+ | 309 | 201 (65.1%) | 108 (35.0%) | |
| Maternal Education | ||||
| High school or less | 109 | 65 (59.6%) | 44 (40.4%) | 0.02 |
| Some college - college graduate | 647 | 404 (62.4%) | 243 (37.6%) | |
| Master’s degree or higher | 432 | 302 (69.9%) | 130 (30.1%) | |
| Parity | ||||
| 0 | 598 | 402 (67.2%) | 196 (32.8%) | 0.13 |
| 1+ | 598 | 377 (63.0%) | 221 (37.0%) | |
| Behavioral Characteristics during Pregnancy | ||||
| Smoking Status | ||||
| Yes | 63 | 39 (61.9%) | 24 (38.1%) | 0.59 |
| No | 1134 | 740 (65.3%) | 394 (34.7%) | |
| Alcohol Use | ||||
| Yes | 365 | 240 (65.8%) | 125 (34.3%) | 0.75 |
| No | 827 | 536 (64.8%) | 291 (35.2%) | |
| Prenatal/Multivitamin Use | ||||
| Yes | 1131 | 742 (65.6%) | 389 (34.4%) | 0.17 |
| No | 63 | 36 (57.1%) | 27 (42.9%) | |
| Infant Characteristics | ||||
| Preterm Birth (birth < 37 weeks) | ||||
| Yes | 39 | 25 (64.1%) | 14 (35.9%) | 0.87 |
| No | 1183 | 773 (65.3%) | 410 (34.7%) | |
| Sex of Child | ||||
| Female | 615 | 399 (64.9%) | 216 (35.1%) | 0.74 |
| Male | 608 | 400 (65.8%) | 208 (34.2%) | |
| Other Characteristics | ||||
| Month of Conception | ||||
| November-March | 254 | 94 (37.0%) | 160 (63.0%) | <0.01 |
| April-October | 971 | 705 (72.6%) | 266 (27.4%) | |
| Vaccination in the Year Prior to Pregnancy | ||||
| Yes | 413 | 295 (71.4%) | 118 (28.6%) | <0.01 |
| No | 812 | 504 (62.1%) | 308 (37.9%) | |
| Infant age (months) at ASQ-3 | ||||
| 5 | 225 | 145 (64.4%) | 80 (35.6%) | 0.79 |
| 6 | 1000 | 654 (65.4%) | 346 (34.6%) | |
| High risk medical conditions | ||||
| Yes | 260 | 170 (65.4%) | 90 (34.6%) | 0.95 |
| No | 965 | 629 (65.2%) | 336 (34.8%) | |
| Influenza or ARI symptoms during pregnancy | ||||
| Influenza-positive/ARI symptoms | 42 | 18 (42.9%) | 24 (57.1%) | <0.01 |
| Influenza negative or not tested/ARI symptoms | 406 | 278 (68.5%) | 128 (31.5%) | |
| Not tested/no ARI symptoms | 777 | 503 (64.7%) | 274 (35.3%) | |
| Site | ||||
| KPNW | 552 | 325 (58.9%) | 227 (41.1%) | <0.01 |
| KPNC | 673 | 474 (70.4%) | 199 (29.6%) | |
Abbreviations: IIV3, trivalent inactivated influenza vaccination, ASQ-3, Ages and Stages Questionnaire Third Edition; ARI, Acute Respiratory Illness; KPNW, Kaiser Permanente North West; KPNC, Kaiser Permanente Northern California