Table 3.
Adjusted Difference in Influenza Vaccination Rate Relative to Control by Time Period.
| Enrollment Period: 9/24/20 to 12/31/20 |
Enrollment Period: 1/1/21 to 3/31/21 |
|||
|---|---|---|---|---|
| Intervention | Adjusted Difference in Percentage Points (95% CI) | Adjusted P Value | Adjusted Difference in Percentage Points (95% CI) | Adjusted P Value |
|
| ||||
| Flu shot reserved for you (2 texts: 72 hr + 24 hr pre-appt) | 4.5 (1.9–7.1) | .02 | 1.1 (−.8–3.1) | .30 |
| Flu shot reserved for you (2 texts: 72 hr + 15 m pre-appt) | 3.7 (1.1–6.4) | .06 | 2.3 (.4–4.3) | .07 |
| Video about getting the flu (2 texts: 3 d + 1 d pre-appt) | 3.3 (.7–5.9) | .09 | 2.4 (.4–4.4) | .07 |
| Protect yourself by getting a flu shot (2 texts: 24 hr + 15 m pre-appt) | 2.0 (−.6–4.7) | .29 | 3.6 (1.6–5.7) | .01 |
| Reply to receive the flu shot reserved for you (1 text: 1 d pre-appt) | 2.9 (.3–5.6) | .15 | 2.4 (.4–4.4) | .07 |
| Dedicate your flu shot to a loved one (2 texts: 3 d + 1 d pre-appt) | 2.0 (−.6–4.7) | .29 | 2.0 (.1–4.0) | .10 |
| Remember to ask for your flu shot (1 text: 1 d pre-appt) | 2.1 (−.5–4.8) | .29 | 1.5 (−.4–3.5) | .19 |
| Protect a vulnerable loved one by getting a flu shot (2 texts: 3 d + 1 d pre-appt) | 1.2 (−1.5–3.8) | .49 | 2.7 (.7–4.7) | .07 |
| Don’t forget to get a flu shot (2 texts: 3 d + 1 d pre-appt) | 2.7 (.0–5.4) | .19 | .7 (−1.2–2.6) | .50 |
| Easy health behavior quiz (1 text: 1 d pre-appt) | 1.8 (−.8–4.5) | .34 | 1.6 (−.3–3.6) | .19 |
| Hard health behavior quiz (1 text: 1 d pre-appt) | 2.4 (−.2–5.1) | .22 | .3 (−1.6–2.2) | .75 |
| Reply to receive the flu shot (1 text: 1 d pre-appt) | 1.0 (−1.7–3.6) | .57 | 2.6 (.6–4.6) | .07 |
| Vivid video about getting the flu (2 texts: 3 d + 1 d pre-appt) | 1.7 (−1.0–4.4) | .36 | 1.6 (−.4–3.5) | .19 |
| Improve the flu shot rate in your region (2 texts: 3 d + 1 hr pre-appt) | 1.5 (−1.1–4.2) | .41 | 1.4 (−.6–3.3) | .24 |
| Video about importance of exercise (2 texts: 3 d + 1 d pre-appt) | 1.2 (−1.5–3.8) | .49 | 1.3 (−.7–3.2) | .25 |
| Beat the flu shot rate in another region (2 texts: 3 d + 1 hr pre-appt) | 1.2 (−1.4–3.8) | .49 | 1.3 (−.6–3.3) | .24 |
| Protect others by getting a flu shot (2 texts: 24 hr + 15 m pre-appt) | .9 (−1.8–3.5) | .59 | 1.8 (−.2–3.7) | .17 |
| Share a joke about the flu (1 text: 1 d pre-appt) | .5 (−2.2–3.1) | .72 | 2.1 (.1–4.1) | .10 |
| Getting a flu shot is an easy way to be healthy (1 text: 1 d pre-appt) | .7 (−1.9–3.3) | .62 | .3 (−1.6–2.2) | .75 |
| Baseline vaccination rate | 44.6% | 7.6% | ||
| Observations | 45,396 | 29,415 | ||
*
Abbreviations: CI=Confidence Interval; hr=hours; d=days; m=minutes; pre-appt=before appointment time.
**
Data presented are difference in predicted vaccination rates relative to usual care Note: There were no significant differences between groups (F = 1.2113, P = .2367).