Table 3.
Selected secondary outcomes
Cohort 1 | Cohort 2 | Combined | ||||||||||||||||
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Placebo | Vaccine | Effect size (95% CI)‡ |
p value | Placebo | Vaccine | Effect size (95% CI)‡ |
p value | Placebo | Vaccine | Effect size (95% CI)‡ |
p value | |||||||
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Cases* | Incidence† | Cases* | Incidence† | Cases* | Incidence† | Cases* | Incidence† | Cases* | Incidence† | Cases* | Incidence† | |||||||
Maternal | ||||||||||||||||||
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All laboratory-confirmed influenza | 30 (639·4) | 46·9 | 17 (662·4) | 25·7 | 0·55 (0·30 to 0·99) | 0·047 | 14 (454·0) | 30·8 | 14 (449·4) | 31·2 | 1·02 (0·48 to 2·18) | 0·956 | 44 (1093·4) | 40·3 | 31 (111·8) | 27·9 | 0·69 (0·44 to 1·10) | 0·122 |
Laboratory-confirmed influenza (pregnancy) | 15 (260·6) | 57·6 | 7 (271·3) | 25·8 | 0·45 (0·18 to 1·10) | 0·078 | 9 (159·8) | 56·3 | 12 (160·7) | 74·7 | 1·38 (0·56 to 3·37) | 0·484 | 24 (420·5) | 57·1 | 19 (431·9) | 44·0 | 0·77 (0·42 to 1·43) | 0·414 |
Laboratory-confirmed influenza (postpartum) | 15 (378·9) | 39·6 | 10 (391·1) | 25·6 | 0·65 (0·28 to 1·47) | 0·299 | 5 (294·1) | 17·0 | 2 (288·7) | 6·9 | 0·41 (0·08 to 2·09) | 0·282 | 20 (672·9) | 29·7 | 12 (679·9) | 17·6 | 0·59 (0·28 to 1·23) | 0·162 |
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Infant | ||||||||||||||||||
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All influenza-like illness | 409 (349·9) | 1168·8 | 439 (363·6) | 1207·4 | 1·04 (0·88 to 1·22) | 0·674 | 328 (270·0) | 1214·9 | 272 (258·7) | 1047·5 | 0·87 (0·71 to 1·05) | 0·145 | 737 (619·9) | 1188·9 | 710 (622·3) | 1140·9 | 0·96 (0·85 to 1·09) | 0·556 |
Preterm (<37 weeks’ gestation) | 145 of (14%) 1023 | NA | 137 (13%) of 1027 | NA | 0·94 (0·76 to 1·17) | 0·584 | 102 (13%) of 790 | NA | 88 (11%) of 782 | NA | 0·87 (0·67 to 1·14) | 0·314 | 247 (14%)of 1813 | NA | 225 (12%) of 1809 | NA | 0·91 (0·77 to 1·08) | 0·289 |
SGA‡ (intergrowth) | 334 (45%) of 741 | NA | 327 (42%) of 764 | NA | 0·95 (0·85 to 1·06) | 0·374 | 229 (41%) of 559 | NA | 211 of (39%) 543 | NA | 0·95 (0·82 to 1·10) | 0·475 | 563 (43%) of 1300 | NA | 538 (41%) of 1307 | NA | 0·95 (0·87 to 1·04) | 0·121 |
SGA (Alexander) | 400 (51%) of 775 | NA | 387 (48%) of 802 | NA | 0·93 (0·85 to 1·03) | 0·182 | 275 (47%) of 580 | NA | 250 (44%) of 573 | NA | 0·92 (0·81 to 1·04) | 0·198 | 675 (50%) of 1355 | NA | 637 (46%) of 1375 | NA | 0·93 (0·86 to 1·01) | 0·068 |
Birthweight, g | 2741·0 (465·3) | NA | 2770·0 (440·6) | NA | 28·9 (−15·6 to 73·5) | 0·203 | 2789·8 (441·8) | NA | 2851·8 (458·6) | NA | 62·0 (10·0 to 113·9) | 0·019 | 2761·9 (455·9) | NA | 2803·9 (449·9) | NA | 42·1 (8·2 to 76·0) | 0·015 |
Gestational age, weeks | 39·4 (2·7) | NA | 39·4 (2·6) | NA | 0·002 (−0·23 to 0·23) | 0·986 | 39·3 (2·4) | NA | 39·5 (2·4) | NA | 0·16 (−0·07 to 0·40) | 0·168 | 39·4 (2·6) | NA | 39·4 (2·5) | NA | 0·07 (−0·09 to 0·24) | 0·386 |
Gestational age <23 weeks and ≥50 weeks dropped because not feasible. Only weights measured within 72 h of birth are presented; weight missing or measured ≥72 h after birth were excluded. Gestational age calculated as date of birth minus date of last menstrual period (estimated recall period of 3–4 weeks). Seven livebirths in cohort 1, three placebo and four in vaccine group, excluded due to vaccination within 14 days of delivery. Nine livebirths in cohort 2, five placebo and five in vaccine group, excluded due to vaccination within 14 days of delivery. Eight dropped from SGA (Alexander) for improbable SGA and weight combination (cohort 1, four placebo, four vaccine). SGA=small for gestational age.
Data are n (person-years); n (%) of N for preterm (<37 weeks gestation), SGA (intergrowth), and SGA (Alexander); or mean (SD) for birthweight and gestational age.
Data are incidence per 1000 person-years.
Effect size is risk ratio for all outcomes except gestational age and birthweight, which are difference between mean values (95% CI).