Table 1.
Characteristics of LAIV‐vaccinated and LAIV‐unvaccinated cohorts
| LAIV vaccinated (n = 138) | LAIV non‐exposed (n = 834 861) | |
|---|---|---|
| n (%) | n (%) | |
| Maternal age at delivery, year | ||
| 14–19 | 18 (13)* | 45 447 (5) |
| 20–34 | 93 (67) | 629 545 (75) |
| 35–43 | 27 (20) | 159 869 (19) |
| Gestational age at birth, week | ||
| ≤36 | 7 (5) | 66 003 (8) |
| >36 | 131 (95) | 768 858 (92) |
| High‐risk medical condition† | ||
| Cardiac disease | 5 (4) | 19 172 (2) |
| Pulmonary disease | 10 (7) | 42 491 (5) |
| Diabetes mellitus | 7 (5) | 25 649 (3) |
| Renal disease | 0 (0) | 1096 (0) |
| Malignancy | 1 (1) | 4752 (1) |
| Immunosuppresive disorder | 0 (0) | 444 (0) |
| Any high‐risk condition | 21 (15) | 86 666 (10) |
| Claim for TIV during pregnancy | 6 (4)† | 96 600 (12) |
| Prenatal visit claims during pregnancy | ||
| 0 | 7 (5) | 48 041 (6) |
| 1–3 | 33 (24) | 225 294 (27) |
| 4–6 | 43 (31) | 291 776 (35) |
| 7–10 | 26 (19) | 164 468 (20) |
| >10 | 29 (21)‡ | 105 282 (13) |
| Trimester at vaccination | ||
| 1st | 65 (47) | NA |
| 2nd | 37 (27) | NA |
| 3rd | 36 (26) | NA |
LAIV, live attenuated influenza vaccine; NA, not applicable; TIV, trivalent inactivated influenza vaccine.
*Significantly different than LAIV non‐exposed, P < 0·0001.
†At least one hospital/emergency department claim or two outpatient claims anytime on or before delivery date.
‡Significantly different than LAIV non‐exposed, P < 0·01.