LB-2. Relative Effectiveness of aIIV3 versus IIV4 and HD-IIV3 In Preventing Influenza-Related Medical Encounters in Adults ≥65 Years of Age at High Risk for Influenza Complications During the U.S. 2017–2018 and 2018–2019 Influenza Seasons
Bibliographic record
Abstract
Abstract Background Individuals with health conditions have shown higher rates of influenza-related morbidity and mortality compared to healthy individuals and are often prioritized for influenza vaccination. However, vaccination with egg-derived standard quadrivalent inactivated influenza vaccines (IIV4) has shown to be less effective in adults ≥65 years of age largely due to immunosenecence. Two enhanced vaccines, the MF59®-adjuvanted trivalent inactivated influenza vaccine (aIIV3) and a high-dose trivalent inactivated influenza vaccine (HD-IIV3), were developed to provide adults ≥65 years with increased protection. The objective of this study was to determine the relative vaccine effectiveness (rVE) of aIIV3 versus IIV4 and HD-IIV3 in preventing influenza-related medical encounters in high-risk adults ≥65 years. Methods A retrospective cohort study was conducted among adults ≥65 years with ≥1 health condition with a record of receiving either aIIV3, IIV4 or HD-IIV3 in the 2017–18 or 2018–19 influenza seasons. Patient-level electronic medical records linked to pharmacy and medical claims were used to ascertain exposure, outcome and covariate information. The primary outcome was influenza-related medical encounters in primary care and hospital (ICD-10 codes J09*–J11*). Inverse probability of treatment weighting was used to obtain odds ratios (ORs) adjusted for age, sex, race, ethnicity, geographic region, comorbidities and week of vaccination for each health condition. rVE was determined using the formula (1-OR)*100 and reported with 95% confidence intervals (CI). Results Overall, 1,755,420 individuals with ≥1 health condition were included for analysis in the 2017–18 season and 2,055,012 individuals in the 2018–19 season. In both seasons, high-risk subjects who received aIIV3 had statistically significantly greater reduction in influenza-related medical encounters as compared to IIV4 (Table 1). Non-statistically significant estimates preclude definitive conclusions for comparisons with HD-IIV3. Table 1. Adjusted relative vaccine effectiveness (rVE) of aIIV3 versus comparators in high-risk patients in the 2017–2018 and 2018–2019 influenza seasons in the U.S. Conclusion The results of this study support the use of aIIV3 in adults ≥65 years of age at high risk for influenza complications and provides further evidence supporting aIIV3 as an effective public health measure against influenza. Disclosures Lauren Fischer, M.A., Seqirus (Consultant) Dan O'Brien, BA, Seqirus (Consultant) Joseph Vasey, PhD, Seqirus (Consultant) Gregg C. Sylvester, MD, Seqirus (Employee) James A. Mansi, PhD, Seqirus (Employee)
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.008 | 0.012 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.004 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".