| Baseline demographics all adults≥18 years old including immunocompromised, excluding recipients of other advanced (Flucelvax, FluAd) and high dose (High dose Fluzone) vaccines | ||||||
|---|---|---|---|---|---|---|
| Measures | Vaccine received |
Vaccination status |
||||
| Recombinant, n = 1,052 |
Standard Dose*, n = 501 |
p Value, recombinant vs. SD | Vaccinated, n = 1,553 |
Unvaccinated, n = 6,249 |
p Value, vaccinated vs. unvaccinated | |
| Age, mean (SD) | 54.2 (19.2) | 45.9 (16.6) | <.001 | 51.5 (18.8) | 46.7 (19.9) | <.001 |
| 0.113 | <.001 | |||||
| White race, ref. = nonwhite, n (%) | 841 (79.9) | 417 (83.2) | 1,258 (81.0) | 4,817 (77.1) | ||
| Female sex, ref. = male, n (%) | 712 (67.7) | 307 (61.3) | 1,019 (65.6) | 3,782 (60.5) | ||
| Season, n (%) | <.001 | <.001 | ||||
| 2018–2019 | 319 (30.3) | 201 (40.1) | 520 (33.5) | 1,377 (22.0) | ||
| 2019–2020 | 733 (69.7) | 300 (59.9) | 1,033 (66.5) | 4,872 (78.0) | ||
| Age group, n (%) | <.001 | <.001 | ||||
| 18–49 years | 296 (28.1) | 199 (39.7) | 495 (31.9) | 2,806 (44.9) | ||
| 50–64 years | 391 (37.2) | 246 (49.1) | 637 (41.0) | 2,066 (33.1) | ||
| ≥65 years | 365 (34.7) | 56 (11.2) | 421 (27.1) | 1,377 (22.0) | ||
| Influenza case, ref. = non-case, n (%) | 197 (187) | 108 (21.6) | 305 (19.6) | 1,928 (30.9) | ||
| Immunocompromised, n (%) | <.001 | <.001 | ||||
| No | 769 (73.1) | 419 (83.6) | 1,188 (76.5) | 5,638 (90.2) | ||
| Yes | 283 (26.9) | 82 (16.4) | 365 (23.5) | 611 (9.8) | ||
| High-risk condition, ref. = no, n (%) |
880 (83.7) |
283 (56.5) |
|
1,163 (74.9) |
2,958 (47.3) |
|
| Effectiveness and relative effectiveness of recombinant and standard dose influenza vaccines against RT-PCR confirmed influenza for all adults≥18 years old including immunocompromised, excluding recipients of other advanced (Flucelvax, FluAd) and high dose (High dose Fluzone) vaccines | ||||||
| Influenza |
Adjusted vaccine effectiveness,* % (95% CI) |
Relative vaccine effectiveness of recombinant vs. standard dose influenza vaccine, % (95% CI) |
||||
| Recombinant (a) |
Standard Dose (b) |
Unadjusted (c) |
Adjusted using a priori variables** (d) |
Adjusted using propensity score (e) |
Adjusted using inverse probability weights (f) |
|
| Overall | 37 (25, 47) | 42 (26, 54) | 13 (−15, 34) | 1 (−34, 26) | 3 (−31, 28) | −3 (−39, 22) |
| Age 18–49 years | 41 (22, 56) | 50 (28, 65) | −16 (−80, 25) | −7 (−70, 33) | −5 (−67, 33) | −10 (−73, 30) |
| Age 50–64 years | 36 (15, 52) | 31 (2, 51) | 21 (−19, 48) | 5 (−50, 40) | 7 (−46, 40) | 6 (−46, 39) |
| Age≥65 years | 30 (1, 51) | 63 (−6, 87) | −73 (−402, 40) | −76 (−427, 41) | −92 (−473, 36) | −112 (−517, 28) |
| Female sex | 39 (25, 51) | 40 (18, 56) | 16 (−19, 40) | 3 (−40, 33) | 5 (−36, 34) | −2 (−46, 29) |
| Male sex | 33 (10, 51) | 45 (17, 63) | 9 (−45, 43) | −8 (−84, 37) | −10 (−87, 35)) | −4 (−72, 38) |
| High Risk Condition | 36 (21, 47) | 29 (2, 49) | 22 (−10, 45) | 12 (−27, 40) | 14 (−24, 40) | 10 (−28, 37) |
| No High-Risk Condition | 38 (11, 56) | 54 (34, 68) | −37 (−124, 17) | −33 (−122, 20) | −34 (−123, 20) | −31 (−117, 22) |
| 2018–2019 Season | 39 (17, 56) | 42 (16, 60) | 9 (−41, 42) | 6 (−51, 42) | 6 (−48, 40) | 4 (−52, 39) |
| 2019–2020 Season | 37 (22, 49) | 40 (18, 57) | 14 (−24, 40) | −4 (−54, 30) | −3 (−52, 30) | −10 (−62, 25) |
| Immunocompromised | 35 (−1, 59)† | 53 (−13, 81)† | −36 (−241, 45) | −85 (−387, 30)† | −76 (−358, 32)† | – |
| Not Immunocompromised | 38 (25, 49) | 41 (23, 54) | 9 (−41, 42) | 6 (−51, 42) | 9 (−25, 34) | 4 (−32, 30) |
Bold indicates non-overlapping confidence intervals. *Standard dose = Afluria, Fluarix, Flulaval and SD Fluzone.
*Adjusted vaccine effectiveness for recombinant and standard dose vaccines (Afluria, Fluarix, Flulaval and SD Fluzone) vs. no vaccination.
**Multivariable logistic regression model adjusted for age, race, sex, season, and high-risk conditions, except that the stratified variable is not included as an adjustment in its own analysis.
Propensity score: Generalized Boosted Regression Method was used to calculate the propensity score using TWANG (Toolkit for Weighting and Analysis of Nonequivalent Groups).
†High-risk not included.