Table 1.
Demographic and Clinical Characteristics and Influenza Vaccination Status of Pregnant People in the 2016–2017 Through the 2021–2022 Influenza Seasons
| Influenza Season | ||||||
|---|---|---|---|---|---|---|
| 2016–2017 | 2017–2018 | 2018–2019 | 2019–2020 | 2020–2021 | 2021–2022 | |
| Pregnant people* | 128,267 | 133,056 | 136,441 | 135,554 | 139,927 | 139,478 |
| Age group (y) | ||||||
| 18–24 | 20,580 (16.0) | 19,831 (14.9) | 19,550 (14.3) | 18,428 (13.6) | 18,432 (13.2) | 17,152 (12.3) |
| 25–34 | 80,042 (62.4) | 83,274 (62.6) | 85,443 (62.6) | 85,005 (62.7) | 88,360 (63.1) | 87,219 (62.5) |
| 35–49 | 27,645 (21.6) | 29,951 (22.5) | 31,448 (23.0) | 32,121 (23.7) | 33,135 (23.7) | 35,107 (25.2) |
| Race and ethnicity | ||||||
| Asian, non-Hispanic | 20,162 (15.7) | 21,119 (15.9) | 22,231 (16.3) | 22,156 (16.3) | 22,406 (16.0) | 22,695 (16.3) |
| Black, non-Hispanic | 8,067 (6.3) | 8,444 (6.3) | 8,662 (6.3) | 8,901 (6.6) | 9,456 (6.8) | 9,336 (6.7) |
| Hispanic | 43,252 (33.7) | 44,967 (33.8) | 46,354 (34.0) | 46,456 (34.3) | 48,383 (34.6) | 50,011 (35.9) |
| White, non-Hispanic | 48,182 (37.6) | 48,988 (36.8) | 49,227 (36.1) | 48,065 (35.5) | 49,000 (35.0) | 46,467 (33.3) |
| None of the above | 5,789 (4.5) | 6,149 (4.6) | 6,541 (4.8) | 6,174 (4.6) | 6,403 (4.6) | 6,564 (4.7) |
| Unknown or missing | 2,815 (2.2) | 3,389 (2.5) | 3,426 (2.5) | 3,802 (2.8) | 4,279 (3.1) | 4,405 (3.2) |
| Pregnancy comorbidities(s)† | 61,716 (48.1) | 67,955 (51.1) | 71,721 (52.6) | 74,095 (54.7) | 78,649 (56.2) | 64,874 (46.5) |
| High-risk condition(s)‡ | 44,543 (34.7) | 47,409 (35.6) | 48,565 (35.6) | 48,660 (35.9) | 51,120 (36.5) | 44,619 (32.0) |
| Health care utilization (no. of encounters)§ | ||||||
| Fewer than 6 | 6,761 (5.3) | 7,026 (5.3) | 7,294 (5.3) | 11,896 (8.8) | 13,166 (9.4) | 10,293 (7.4) |
| 6–10 | 22,597 (17.6) | 23,302 (17.5) | 23,361 (17.1) | 25,581 (18.9) | 30,832 (22.0) | 27,703 (19.9) |
| 11–20 | 57,786 (45.1) | 58,915 (44.3) | 60,258 (44.2) | 59,529 (43.9) | 58,587 (41.9) | 60,171 (43.1) |
| More than 20 | 41,123 (32.1) | 43,813 (32.9) | 45,528 (33.4) | 38,548 (28.4) | 37,342 (26.7) | 41,311 (29.6) |
| Influenza vaccine receipt‖ | 80,787 (63.0) | 85,762 (64.5) | 92,354 (67.7) | 96,202 (71.0) | 92,436 (66.1) | 78,683 (56.4) |
Data are n or n (column %).
Eligible pregnancies spanned at least 1 day during the August 1 through March 31 period of an influenza season and met enrollment criteria.
Individuals with at least one complication or comorbidity. Predefined pregnancy comorbidities or complications included the following, identified in the electronic health record during the pregnancy: diabetes or hypertension; liver disorders; renal disease; nervous system, respiratory, or digestive system diseases complicating pregnancy; obesity complicating pregnancy; alcohol use, drug use, smoking complicating pregnancy (Appendix 5, available online at http://links.lww.com/AOG/D258).
Individuals with at least one condition. Predefined conditions associated with increased risk of severe illness and complications from influenza (high-risk conditions) included the following, identified in the electronic health record during the pregnancy: cardiac, cerebrovascular, chronic pulmonary, liver, peptic ulcer, peripheral vascular, or renal diseases; diabetes; nondiabetic metabolic, endocrine, immunosuppressive, or neurologic or musculoskeletal disorders; hemoglobinopathies; long-term medication use; malignancy; morbid obesity (Appendix 7, available online at http://links.lww.com/AOG/D258).
Number of medical encounters in the July 1 through June 30 period overlapping the influenza season of interest.
Receipt of same-season influenza vaccine between August 1 and March 31, including before, during, or after pregnancy.