Table 2. Trend of influenza vaccination rate using the KNHANES between 2007–2020

Trends in influenza vaccinated
Pre-COVID-19 pandemic era COVID-19 pandemic
2007–2008 2009–2010 2011–2012 2014–2015 2016–2017 2018–2019 2020
Number, n (%) 3,598 (11.51) 4,959 (15.86) 4,998 (15.99) 4,324 (13.83) 5,247 (16.78) 5,507 (17.62) 2,630 (8.41)
Weighted % (95% CI)
Overall 27.6 (26.2–29.0) 27.7 (26.5–28.8) 32.5 (31.1–33.9) 33.0 (31.7–34.3) 35.9 (34.7–37.0) 38.7 (37.4–40.1) 42.2 (40.0–44.3)
Age, years
14–18 13.5 (10.0–16.9) 17.8 (14.6–21.1) 25.4 (21.7–29.2) 22.1 (18.7–25.6) 18.9 (15.7–22.1) 27.2 (23.1–31.3) 43.0 (34.7–51.3)
19–64 22.5 (21.2–23.8) 21.2 (20.1–22.2) 25.7 (24.3–27.0) 25.3 (24.0–26.7) 28.2 (27.1–29.4) 30.2 (28.8–31.6) 34.7 (32.5–36.9)
≥65 72.9 (70.2–75.5) 75.7 (73.4–77.9) 78.7 (76.6–80.7) 81.0 (79.1–82.9) 83.4 (81.8–85.0) 85.5 (83.8–87.1) 81.4 (78.8–84.0)
Sex
Male 24.0 (22.4–25.7) 24.2 (22.9–25.6) 28.4 (26.7–30.1) 27.5 (26.0–29.1) 30.8 (29.4–32.3) 33.6 (32.0–35.2) 37.6 (35.0–40.3)
Female 31.1 (29.4–32.8) 31.1 (29.7–32.5) 36.5 (34.9–38.1) 38.3 (36.6–39.9) 40.8 (39.3–42.3) 43.8 (42.2–45.4) 46.8 (44.2–49.5)
Income
Lowest quartile 24.8 (22.4–27.2) 25.4 (23.3–27.5) 32.1 (29.8–34.4) 32.3 (29.8–34.8) 34.6 (32.3–36.9) 38.1 (35.6–40.6) 38.9 (35.5–42.4)
Second quartile 27.5 (25.2–29.9) 28.1 (26.1–30.2) 32.4 (29.9–34.9) 31.4 (29.0–33.8) 35.0 (32.8–37.1) 37.0 (34.6–39.4) 42.2 (38.4–45.9)
Third quartile 27.6 (25.2–29.9) 27.3 (25.3–29.2) 32.9 (30.5–35.2) 32.8 (30.5–35.1) 35.7 (33.6–37.9) 38.6 (36.3–41.0) 45.0 (41.4–48.6)
Highest quartile 30.2 (27.6–32.8) 30.1 (28.1–32.1) 32.7 (30.4–35.0) 35.5 (33.2–37.8) 38.1 (35.7–40.5) 41.1 (38.8–43.5) 42.4 (38.6–46.1)
Education
High school or lower 32.3 (30.4–34.1) 32.4 (30.8–34.0) 38.0 (36.3–39.7) 39.2 (37.5–40.8) 43.9 (42.3–45.4) 46.7 (45.0–48.4) 50.8 (47.9–53.6)
College or higher 19.6 (17.8–21.4) 20.1 (18.6–21.6) 24.0 (22.3–25.7) 25.5 (23.8–27.2) 27.3 (25.8–28.7) 30.6 (28.9–32.3) 34.3 (31.8–36.7)
Alcohol consumption
No 35.9 (33.1–38.7) 40.4 (37.7–43.2) 43.5 (40.3–46.8) 43.0 (40.2–45.7) 46.9 (44.0–49.9) 49.7 (46.6–52.9) 55.8 (50.0–61.6)
Yes 26.1 (24.7–27.6) 25.5 (24.3–26.6) 30.7 (29.3–32.1) 31.4 (30.0–32.7) 34.2 (33.0–35.5) 37.3 (35.9–38.7) 40.4 (38.3–42.5)
Smoking
Non-smoker 28.7 (27.1–30.3) 29.6 (28.2–31.0) 34.9 (33.2–36.6) 35.5 (33.9–37.1) 38.3 (36.8–39.7) 41.6 (40.0–43.3) 45.5 (42.8–48.2)
Smoker 20.9 (18.7–23.1) 19.2 (17.4–20.9) 23.7 (21.6–25.8) 22.0 (19.8–24.2) 24.8 (22.8–26.8) 26.0 (23.9–28.1) 30.9 (27.0–34.7)
Ex-smoker 33.0 (30.4–35.6) 33.2 (31.1–35.4) 36.3 (33.7–38.9) 36.7 (34.3–39.1) 39.8 (37.6–41.9) 42.2 (40.0–44.5) 42.6 (39.0–46.2)
Nationwide health screening within 2 years
Yes 34.8 (33.0–36.7) 34.3 (32.6–35.9) 38.5 (36.8–40.3) 38.1 (36.5–39.7) 40.9 (39.4–42.4) 42.9 (41.4–44.5) 46.8 (44.3–49.2)
No 21.6 (20.1–23.2) 21.5 (20.2–22.8) 26.4 (24.7–28.1) 26.6 (25.0–28.3) 27.7 (26.1–29.3) 31.1 (29.2–32.9) 33.7 (30.8–36.5)
Medical condition
With medical condition 43.3 (40.8–45.8) 44.2 (42.2–46.2) 49.9 (47.7–52.1) 50.7 (48.7–52.7) 53.6 (51.7–55.5) 56.3 (54.3–58.2) 55.7 (52.8–58.7)
Without medical condition 22.1 (20.6–23.6) 21.5 (20.3–22.7) 26.0 (24.6–27.5) 25.6 (24.2–26.9) 27.4 (26.1–28.6) 30.1 (28.6–31.6) 35.0 (32.6–37.4)
Abbreviations: CI, confidence interval; KNHANES, Korea National Health and Nutrition Examination Survey.
Medical conditions include one or more of the following conditions: diabetes, tuberculosis, asthma, angina, myocardial infarction, cancer, chronic kidney disease, hypertension, and hyperlipidemia.