Comparison of Number of Visits (Mean ±SD) during 4 Influenza Vaccination Seasons
| Visits | 1998 to 1999 | 1999 to 2000 | 2000 to 2001 | 2001 to 2002 | ||||
|---|---|---|---|---|---|---|---|---|
| Vaccinated (n = 106) | Not Vaccinated (n = 99) | Vaccinated (n = 122) | Not Vaccinated (n = 91) | Vaccinated (n = 89) | Not Vaccinated (n = 128) | Vaccinated (n = 119) | Not Vaccinated (n = 98 | |
| Oct–Nov | 1.13 ± 0.77* | 0.35 ± 0.69 | 0.99 ± 0.66* | 0.44 ± 0.69 | 0.78 ± 0.96 | 0.70 ± 0.77 | 1.20 ± 0.91* | 0.62 ± 0.75 |
| Dec–Feb | 0.89 ± 0.91 | 0.78 ± 0.91 | 0.93 ± 0.99 | 0.68 ± 0.92 | 1.06 ± 1.24* | 0.79 ± 0.88 | —† | — |
| Oct–Feb | 2.02 ± 1.23* | 1.13 ± 1.27 | 1.92 ± 1.16* | 1.12 ± 1.16 | 2.37 ± 1.63* | 1.48 ± 1.17 | — | — |
* Difference between vaccinated and unvaccinated is significant at the P < .001 level.
† Visits in January and February 2002 were not collected.