scholarly journals Relative Effectiveness of the Cell-Derived Inactivated Quadrivalent Influenza Vaccine Versus Egg-Derived Inactivated Quadrivalent Influenza Vaccines in Preventing Influenza-Related Medical Encounters During the 2018-2019 Influenza Season in the United States

2021 ◽  
Author(s):  
Constantina Boikos ◽  
Lauren Fischer ◽  
Dan O’Brien ◽  
Joe Vasey ◽  
Gregg C Sylvester ◽  
...  
Keyword(s):  
Influenza Vaccine ◽  
Influenza Season ◽  
Relative Effectiveness ◽  
The United States ◽  
Geographic Region ◽  
Vaccine Effectiveness ◽  
Influenza Viruses ◽  
Study Cohort ◽  
Doubly Robust ◽  
Quadrivalent Influenza Vaccine

Abstract Background The cell-propagated inactivated quadrivalent influenza vaccine (ccIIV4) may offer improved protection in seasons where egg-derived influenza viruses undergo mutations that affect antigenicity. This study estimated the relative vaccine effectiveness (rVE) of ccIIV4 versus egg-derived inactivated quadrivalent influenza vaccine (eIIV4) in preventing influenza-related medical encounters in the 2018-2019 U.S. season. Methods A dataset linking primary care electronic medical records with medical claims data was used to conduct a retrospective cohort study among individuals ≥4 years vaccinated with ccIIV4 or eIIV4 during the 2018-2019 season. Adjusted odds ratios (ORs) were derived from a doubly robust inverse probability of treatment-weighted approach adjusting for age, sex, race, ethnicity, geographic region, vaccination week, and health status. Relative vaccine effectiveness (rVE) was estimated by (1-OR)*100 and presented with 95% confidence intervals (CI). Results Following the application of inclusion/exclusion criteria, the study cohort included 2,125,430 ccIIV4 and 8,000,903 eIIV4 recipients. Adjusted analyses demonstrated a greater reduction in influenza-related medical encounters with ccIIV4 versus eIIV4, with the following rVE: overall, 7.6% (95% CI 6.5-8.6); age 4-17 years, 3.9% (0.9-7.0); 18-64 years, 6.5% (5.2-7.9); 18-49 years, 7.5% (5.7-9.3); 50-64 years, 5.6% (3.6-7.6); and ≥65 years, -2.2% (-5.4 to 0.9). Conclusions Adjusted analyses demonstrated statistically significantly greater reduction in influenza-related medical encounters in individuals vaccinated with ccIIV4 vs eIIV4 in the 2018-2019 U.S. influenza season. These results support ccIIV4 as a potentially more effective public health measure against influenza than an egg-based equivalent.

scholarly journals Effectiveness of the Cell–Derived Inactivated Quadrivalent Influenza Vaccine in Individuals at High Risk of Influenza Complications in the 2018-2019 US Influenza Season

2021 ◽  
Author(s):  
Constantina Boikos ◽  
Mahrukh Imran ◽  
Van Hung Nguyen ◽  
Thierry Ducruet ◽  
Gregg C Sylvester ◽  
...  
Keyword(s):  
High Risk ◽  
Influenza Vaccine ◽  
Influenza Season ◽  
Health Condition ◽  
Geographic Region ◽  
Vaccine Effectiveness ◽  
Influenza Viruses ◽  
Influenza Vaccines ◽  
Study Cohort ◽  
Medical Conditions

Abstract Background Higher rates of influenza-related morbidity and mortality occur in individuals with underlying medical conditions. To improve vaccine effectiveness, cell-based technology for influenza vaccine manufacturing has been developed. Cell–derived inactivated quadrivalent influenza vaccines (cIIV4) may improve protection in seasons where egg-propagated influenza viruses undergo mutations that affect antigenicity. This study aimed to estimate the relative vaccine effectiveness (rVE) of cIIV4 versus egg-derived inactivated quadrivalent influenza vaccines (eIIV4) in preventing influenza-related medical encounters in individuals with underlying medical conditions putting them at high risk of influenza complications during the 2018-2019 U.S. influenza season. Methods An integrated dataset, linking primary care electronic medical records with claims data, was used to conduct a retrospective cohort study among individuals aged ≥4 years, with ≥1 health condition, vaccinated with cIIV4 or eIIV4 during the 2018-2019 season. Adjusted odds ratios (ORs) were derived using a doubly robust inverse probability of treatment-weighting (IPTW) model, adjusting for age, sex, race, ethnicity, geographic region, vaccination week, and health status. rVE was estimated by (1- OR)*100 and presented with 95% confidence intervals (CI). Results The study cohort included 471,301 cIIV4 and 1,641,915 eIIV4 recipients. Compared with eIIV4, cIIV4 prevented significantly more influenza-related medical encounters among individuals with ≥1 health condition (rVE 13.4% [95% CI 11.4-15.4]); chronic pulmonary disease (18.7% [16.0-21.3]); and rheumatic disease (11.8% [3.6-19.3]). Conclusions Our findings support the use of cIIV4 in individuals ≥4 years of age at high risk of influenza complications and provide further evidence supporting improved effectiveness of cIIV4 compared to eIIV4.

scholarly journals Relative Effectiveness of the Cell-Cultured Quadrivalent Influenza Vaccine Compared to Standard, Egg-derived Quadrivalent Influenza Vaccines in Preventing Influenza-like Illness in 2017–2018

2020 ◽  
Vol 71 (10) ◽  
pp. e665-e671 ◽  
Author(s):  
Constantina Boikos ◽  
Gregg C Sylvester ◽  
John S Sampalis ◽  
James A Mansi
Keyword(s):  
Cell Culture ◽  
Health Status ◽  
Influenza Vaccine ◽  
Influenza Season ◽  
Relative Effectiveness ◽  
Geographic Region ◽  
Influenza Vaccines ◽  
Study Cohort ◽  
Influenza Like Illness ◽  
Adaptive Mutations

Abstract Background Influenza antigens may undergo adaptive mutations during egg-based vaccine production. In the 2017–2018 influenza season, quadrivalent, inactivated cell-derived influenza vaccine (ccIIV4) vaccine was produced using A(H3N2) seed virus propagated exclusively in cell culture, thus lacking egg adaptive changes. This United States study estimated relative vaccine effectiveness (rVE) of ccIIV4 vs egg-derived quadrivalent vaccines (egg-derived IIV4) for that season. Methods Vaccination, outcome, and covariate data were ascertained retrospectively from a electronic medical record (EMR) dataset and analyzed. The study cohort included patients ≥ 4 years of age. rVE was estimated against influenza-like illness (ILI) using diagnostic International Classification of Diseases, Ninth or Tenth Revision codes. The adjusted odds ratios used to derive rVE estimates were estimated from multivariable logistic regression models adjusted for age, sex, race/ethnicity, geographic region, and health status. Results Overall, 92 187 individuals had a primary care EMR record of ccIIV4 and 1 261 675 had a record of egg-derived IIV4. In the ccIIV4 group, 1705 narrowly defined ILI events occurred, and 25 645 occurred in the standard egg-derived IIV4 group. Crude rVE was 9.2% (95% confidence interval [CI], 4.6%–13.6%). When adjusted for age, sex, health status, comorbidities, and geographic region, the estimated rVE changed to 36.2% (95% CI, 26.1%–44.9%). Conclusions ccIIV4, derived from A(H3N2) seed virus propagated exclusively in cell culture, was more effective than egg-derived IIV4 in preventing ILI during the 2017–2018 influenza season. This result suggests that cell-derived influenza vaccines may have greater effectiveness than standard egg-derived vaccines.

scholarly journals A Real-World Clinical and Economic Analysis of Cell-derived Quadrivalent Influenza Vaccine Compared to Standard Egg-derived Quadrivalent Influenza Vaccines During the 2019-20 Influenza Season in the United States

2021 ◽  
Author(s):  
Victoria Divino ◽  
Vamshi Ruthwik Anupindi ◽  
Mitch DeKoven ◽  
Joaquin Mould-Quevedo ◽  
Stephen I Pelton ◽  
...  
Keyword(s):  
High Risk ◽  
Influenza Vaccine ◽  
Influenza Season ◽  
The United States ◽  
Vaccine Effectiveness ◽  
Influenza Vaccines ◽  
Sensitivity Analyses ◽  
Administrative Claims ◽  
Adaptive Mutations ◽  
Quadrivalent Influenza Vaccine

Abstract Background Cell-derived influenza vaccines are not subject to egg adaptive mutations that have potential to decrease vaccine effectiveness. This retrospective analysis estimated the relative vaccine effectiveness (rVE) of cell-derived quadrivalent influenza vaccine (IIV4c) compared to standard egg-derived quadrivalent influenza vaccines (IIV4e) among recipients aged 4-64 years in the US during the 2019-20 influenza season. Methods The IQVIA PharMetrics® Plus administrative claims database was utilized. Study outcomes were assessed post-vaccination through the end of the study period (March 7, 2020). Inverse probability of treatment weighting (IPTW) was implemented to adjust for covariate imbalance. Adjusted rVE against influenza-related hospitalizations/emergency room (ER) visits and other clinical outcomes was estimated through IPTW-weighted Poisson regression models for the IIV4c and IIV4e cohorts and for the subgroup with ≥1 high-risk condition. Sensitivity analyses modifying the outcome assessment period as well as a doubly-robust analysis were also conducted. IPTW-weighted generalized linear models were used to estimate predicted annualized all-cause costs. Results The final sample comprised 1,138,969 IIV4c and 3,926,357 IIV4e recipients following IPTW adjustment. IIV4c was more effective in preventing influenza-related hospitalizations/ER visits as well as respiratory-related hospitalizations/ER visits compared to IIV4e. IIV4c was also more effective for the high-risk subgroup and across the sensitivity analyses. IIV4c was also associated with significantly lower annualized all-cause total costs compared to IIV4e (-$467), driven by lower costs for outpatient medical services and inpatient hospitalizations. Conclusions IIV4c was significantly more effective in preventing influenza-related hospitalizations/ER visits compared to IIV4e and was associated with significantly lower all-cause costs.

scholarly journals 1341. Relative Vaccine Effectiveness Against Influenza-related Hospitalizations and Respiratory Events During the 2019/20 Influenza seAson in U.S. Children and Adults. A Real-World Evidence Comparison Between Quadrivalent Cell-based and Egg-based Influenza Vaccines

2021 ◽  
Vol 8 (Supplement_1) ◽  
pp. S758-S758
Author(s):  
Stephen I Pelton ◽  
Maarten Postma ◽  
Victoria Divino ◽  
Joaquin F Mould-Quevedo ◽  
Ruthwik Anupindi ◽  
...  
Keyword(s):  
High Risk ◽  
Influenza Vaccine ◽  
Influenza Season ◽  
Standard Dose ◽  
The United States ◽  
Negative Control ◽  
Vaccine Effectiveness ◽  
Administrative Claims ◽  
Real World Evidence ◽  
Quadrivalent Influenza Vaccine

Abstract Background Non-egg-based influenza vaccine manufacturing reduces egg adaptation and therefore has the potential to increase vaccine effectiveness. This study evaluated whether the cell-based quadrivalent influenza vaccine (QIVc) improved relative vaccine effectiveness (rVE) compared to standard-dose egg-based quadrivalent influenza vaccine (QIVe-SD) in the reduction of influenza-related and respiratory-related hospitalizations/emergency room (ER) visits among subjects 4-64 years old during the 2019/20 influenza season. Methods A retrospective analysis was conducted among subjects 4-64 years old vaccinated with QIVc or QIVe-SD using administrative claims data in the United States of America (U.S.) (IQVIA PharMetrics® Plus). Inverse probability of treatment weighting (IPTW) was used to adjust for baseline confounders. Post-IPTW, the number of events and rates (per 1,000 vaccinated subject-seasons) of influenza-related hospitalizations/ER visits, respiratory-related hospitalizations/ER visits and all-cause hospitalizations were assessed. Poisson regression was used to estimate adjusted rVE. To avoid any influenza outcome misclassification with COVID-19 infection, the study period ended March 7,2020. A sub-analysis for a high-risk subgroup was conducted. Urinary tract infection (UTI) hospitalization was assessed as a negative control endpoint. Results During the 2019/20 influenza season, 1,150,134 QIVc and 3,924,819 QIVe-SD recipients were identified post-IPTW. Overall adjusted analyses (4-64 years old) found that QIVc was associated with a significantly higher rVE compared to QIVe-SD against influenza-related hospitalizations/ER visits (5.3% [95% CI: 0.5%-9.9%]), all-cause hospitalizations (14.5% [95% CI: 13.1%-15.8%]) and any respiratory-related hospitalization/ER visit (8.2% [95% CI: 6.5%-9.8%]). A similar trend was seen for the high-risk subgroup; for instance, rVE for QIVc compared to QIVe-SD against influenza-related hospitalizations/ER visits was 10.5% [95% CI: 2.9%-17.4%]. No effect was identified for the negative control outcome. Conclusion QIVc was significantly more effective in preventing influenza-related and respiratory-related hospitalizations/ER visits, as well as all-cause hospitalizations, compared to QIVe-SD. Disclosures Stephen I. Pelton, MD, Seqirus (Consultant) Maarten Postma, Dr., Seqirus (Consultant) Victoria Divino, PhD, Seqirus (Consultant) Joaquin F. Mould-Quevedo, PhD, Seqirus (Employee) Ruthwik Anupindi, PhD, Seqirus (Consultant) Mitchell DeKoven, PhD, Seqirus (Consultant) myron J. levin, MD, GSK group of companies (Employee, Research Grant or Support)

scholarly journals Effects of Influenza Vaccination in the United States During the 2018–2019 Influenza Season

2020 ◽  
Vol 71 (8) ◽  
pp. e368-e376 ◽  
Author(s):  
Jessie R Chung ◽  
Melissa A Rolfes ◽  
Brendan Flannery ◽  
Pragati Prasad ◽  
Alissa O’Halloran ◽  
...  
Keyword(s):  
United States ◽  
Influenza Vaccine ◽  
Influenza Vaccination ◽  
Influenza Season ◽  
The United States ◽  
Vaccine Effectiveness ◽  
Influenza Viruses ◽  
Monte Carlo Algorithm ◽  
Medical Visits ◽  
The Us

Abstract Background Multivalent influenza vaccine products provide protection against influenza A(H1N1)pdm09, A(H3N2), and B lineage viruses. The 2018–2019 influenza season in the United States included prolonged circulation of A(H1N1)pdm09 viruses well-matched to the vaccine strain and A(H3N2) viruses, the majority of which were mismatched to the vaccine. We estimated the number of vaccine-prevented influenza-associated illnesses, medical visits, hospitalizations, and deaths for the season. Methods We used a mathematical model and Monte Carlo algorithm to estimate numbers and 95% uncertainty intervals (UIs) of influenza-associated outcomes prevented by vaccination in the United States. The model incorporated age-specific estimates of national 2018–2019 influenza vaccine coverage, influenza virus–specific vaccine effectiveness from the US Influenza Vaccine Effectiveness Network, and disease burden estimated from population-based rates of influenza-associated hospitalizations through the Influenza Hospitalization Surveillance Network. Results Influenza vaccination prevented an estimated 4.4 million (95%UI, 3.4 million–7.1 million) illnesses, 2.3 million (95%UI, 1.8 million–3.8 million) medical visits, 58 000 (95%UI, 30 000–156 000) hospitalizations, and 3500 (95%UI, 1000–13 000) deaths due to influenza viruses during the US 2018–2019 influenza season. Vaccination prevented 14% of projected hospitalizations associated with A(H1N1)pdm09 overall and 43% among children aged 6 months–4 years. Conclusions Influenza vaccination averted substantial influenza-associated disease including hospitalizations and deaths in the United States, primarily due to effectiveness against A(H1N1)pdm09. Our findings underscore the value of influenza vaccination, highlighting that vaccines measurably decrease illness and associated healthcare utilization even in a season in which a vaccine component does not match to a circulating virus.

scholarly journals Influenza vaccine effectiveness against hospitalization in the United States, 2019-2020

2020 ◽  
Author(s):  
Mark W Tenforde ◽  
H Keipp Talbot ◽  
Christopher H Trabue ◽  
Manjusha Gaglani ◽  
Tresa M McNeal ◽  
...  
Keyword(s):  
United States ◽  
Influenza Vaccine ◽  
Influenza Vaccination ◽  
Respiratory Illness ◽  
The United States ◽  
Vaccine Effectiveness ◽  
Influenza Viruses ◽  
Current Season ◽  
Hospital Resources ◽  
Negative Controls

Abstract Background Influenza causes significant morbidity and mortality and stresses hospital resources during periods of increased circulation. We evaluated the effectiveness of the 2019-2020 influenza vaccine against influenza-associated hospitalizations in the United States. Methods We included adults hospitalized with acute respiratory illness at 14 hospitals and tested for influenza viruses by reserve transcription polymerase chain reaction. Vaccine effectiveness (VE) was estimated by comparing the odds of current-season influenza vaccination in test-positive influenza cases versus test-negative controls, adjusting for confounders. VE was stratified by age and major circulating influenza types along with A(H1N1)pdm09 genetic subgroups. Results 3116 participants were included, including 18% (553) influenza-positive cases. Median age was 63 years. Sixty-seven percent (2079) received vaccination. Overall adjusted VE against influenza viruses was 41% (95% confidence interval [CI]: 27-52). VE against A(H1N1)pdm09 viruses was 40% (95% CI: 24-53) and 33% against B viruses (95% CI: 0-56). Of the two major A(H1N1)pdm09 subgroups (representing 90% of sequenced H1N1 viruses), VE against one group (5A+187A,189E) was 59% (95% CI: 34-75) whereas no significant VE was observed against the other group (5A+156K) [-1%, 95% CI: -61-37]. Conclusions In a primarily older population, influenza vaccination was associated with a 41% reduction in risk of hospitalized influenza illness.

scholarly journals 150. Relative Effectiveness of High-Dose and Standard-Dose Influenza Vaccine Against Influenza-Related Hospitalization Among Older Adults—United States, 2015–2017

2018 ◽  
Vol 5 (suppl_1) ◽  
pp. S10-S10
Author(s):  
Joshua Doyle ◽  
Lauren Beacham ◽  
Elif Alyanak ◽  
Manjusha Gaglani ◽  
Emily T Martin ◽  
...  
Keyword(s):  
United States ◽  
Older Adults ◽  
Influenza Vaccine ◽  
Influenza A ◽  
Standard Dose ◽  
Relative Effectiveness ◽  
The United States ◽  
Vaccine Effectiveness ◽  
High Dose ◽  
Research Grant

Abstract Background Seasonal influenza causes substantial morbidity and mortality, and older adults are disproportionately affected. Newer vaccines have been developed for use in people 65 years and older, including a trivalent inactivated vaccine with a 4-fold higher dose of antigen (IIV-HD). In recent years, the use of IIV-HD has increased sufficiently to evaluate its effectiveness compared with standard-dose inactivated influenza vaccines (IIV-SD). Methods Hospitalized patients with acute respiratory illness were enrolled in an observational vaccine effectiveness study at 8 hospitals in 4 states participating in the United States Hospitalized Adult Influenza Vaccine Effectiveness Network during the 2015–2016 and 2016–2017 influenza seasons. Predominant influenza A virus subtypes were H1N1 and H3N2, respectively, during these seasons. All enrolled patients were tested for influenza virus with polymerase chain reaction. Receipt and type of influenza vaccine was determined from electronic records and chart review. Odds of laboratory-confirmed influenza were compared among vaccinated and unvaccinated patients. Relative odds of laboratory-confirmed influenza were determined for patients who received IIV-HD or IIV-SD, and adjusted for potential confounding variables via logistic regression. Results Among 1,744 enrolled patients aged ≥ 65 years, 1,105 (63%) were vaccinated; among those vaccinated, 621 (56%) received IIV-HD and 484 (44%) received IIV-SD. Overall, 315 (18%) tested positive for influenza, including 97 (6%) who received IIV-HD, 86 (5%) who received IIV-SD, and 132 (8%) who were unvaccinated. Controlling for age, race, sex, enrollment site, date of illness, index of comorbidity, and influenza season, the adjusted odds of influenza among patients vaccinated with IIV-HD vs. IIV-SD were 0.72 (P = 0.06, 95% CI: 0.52 to 1.01). Conclusion Comparison of high-dose vs. standard-dose vaccine effectiveness during 2 recent influenza seasons (1 H1N1 and 1 H3N2-predominant) suggested relative benefit (nonsignificant) of high-dose influenza vaccine in protecting against influenza-associated hospitalization among persons aged 65 years and older; additional years of data are needed to confirm this finding. Disclosures H. K. Talbot, sanofi pasteur: Investigator, Research grant. Gilead: Investigator, Research grant. MedImmune: Investigator, Research grant. Vaxinnate: Safety Board, none. Seqirus: Safety Board, none.

scholarly journals Relative and Absolute Effectiveness of High-Dose and Standard-Dose Influenza Vaccine Against Influenza-Related Hospitalization Among Older Adults—United States, 2015–2017

2020 ◽  
Author(s):  
Joshua D Doyle ◽  
Lauren Beacham ◽  
Emily T Martin ◽  
H Keipp Talbot ◽  
Arnold Monto ◽  
...  
Keyword(s):  
United States ◽  
Older Adults ◽  
Influenza Vaccine ◽  
Standard Dose ◽  
Relative Effectiveness ◽  
Respiratory Illness ◽  
The United States ◽  
Vaccine Effectiveness ◽  
High Dose ◽  
Confounding Variables

Abstract Background Seasonal influenza causes substantial morbidity and mortality in older adults. High-dose inactivated influenza vaccine (HD-IIV), with increased antigen content compared to standard-dose influenza vaccines (SD-IIV), is licensed for use in people aged ≥65 years. We sought to evaluate the effectiveness of HD-IIV and SD-IIV for prevention of influenza-associated hospitalizations. Methods Hospitalized patients with acute respiratory illness were enrolled in an observational vaccine effectiveness study at 8 hospitals in the United States Hospitalized Adult Influenza Vaccine Effectiveness Network during the 2015–2016 and 2016–2017 influenza seasons. Enrolled patients were tested for influenza, and receipt of influenza vaccine by type was recorded. Effectiveness of SD-IIV and HD-IIV was estimated using a test-negative design (comparing odds of influenza among vaccinated and unvaccinated patients). Relative effectiveness of SD-IIV and HD-IIV was estimated using logistic regression. Results Among 1487 enrolled patients aged ≥65 years, 1107 (74%) were vaccinated; 622 (56%) received HD-IIV, and 485 (44%) received SD-IIV. Overall, 277 (19%) tested positive for influenza, including 98 (16%) who received HD-IIV, 87 (18%) who received SD-IIV, and 92 (24%) who were unvaccinated. After adjusting for confounding variables, effectiveness of SD-IIV was 6% (95% confidence interval [CI] −42%, 38%) and that of HD-IIV was 32% (95% CI −3%, 54%), for a relative effectiveness of HD-IIV versus SD-IIV of 27% (95% CI −1%, 48%). Conclusions During 2 US influenza seasons, vaccine effectiveness was low to moderate for prevention of influenza hospitalization among adults aged ≥65 years. High-dose vaccine offered greater effectiveness. None of these findings were statistically significant.

scholarly journals 988. Effectiveness of Seasonal Influenza Vaccines Against Influenza A(H3N2) Illness Among Children Aged <18 Years, US Flu VE Network, 2010–2018

2018 ◽  
Vol 5 (suppl_1) ◽  
pp. S292-S292
Author(s):  
Brendan L Flannery ◽  
Jessie Chung ◽  
Michael L Jackson ◽  
Lisa A Jackson ◽  
Arnold S Monto ◽  
...  
Keyword(s):  
Influenza Vaccine ◽  
Influenza A ◽  
The United States ◽  
Vaccine Effectiveness ◽  
Influenza Viruses ◽  
Older Children ◽  
Research Support ◽  
Illness Onset ◽  
Negative Controls ◽  
Research Grant

Abstract Background Interim estimates of 2017–2018 influenza vaccine effectiveness (VE) against influenza A(H3N2)-related illness in the United States indicated better protection among young children than among older children and adolescents. We examined VE against influenza A(H3N2) illness during five A(H3N2)-predominant seasons from 2010–2011 through 2016–2017 to investigate differences between VE among younger vs. older children. Methods We analyzed data from 11,736 outpatients aged &lt;18 years with medically attended acute respiratory illnesses enrolled at US Flu VE Network study sites during five influenza A(H3N2)-predominant seasons. Respiratory specimens from all enrollees were tested for influenza viruses using reverse transcription PCR. Children with documented receipt of the recommended number of doses of current season inactivated influenza vaccine at least 14 days before illness onset were considered fully vaccinated; partially vaccinated children and those who received live attenuated influenza vaccine were excluded. Vaccine effectiveness was estimated as 100 × (1 – adjusted odds ratio) from multivariable logistic regression adjusting for study site, age, sex, presence of high-risk medical conditions, and days from illness onset to enrollment comparing odds of vaccination among A(H3N2)-positive cases vs. influenza-negative controls. Results A total of 1,854 influenza A(H3N2) cases and 9,882 influenza-negative controls were included; 494 (28%) influenza A(H3N2) cases and 3,637 (41%) controls were fully vaccinated before illness onset. VE ranged from 26% (95% confidence interval [CI], −17% to 53%) to 60% (38%–75%) among children aged 6 months–4 years and from 9% (−16% to 29%) to 66% (37%–82%) among 5–17 year olds (figure). During 2012–2013 and 2014–2015, A(H3N2) VE estimates were significantly higher among younger compared with older children (P &lt; 0.05); in other seasons before 2017–2018, A(H3N2) VE estimates were similar among younger and older children. Conclusion Higher VE against A(H3N2) viruses in younger vs. older children in some seasons suggests immunologic differences in response to vaccine components. Overall, inactivated influenza vaccine provided moderate protection against A(H3N2)-related illness among children. Disclosures M. L. Jackson, sanofi pasteur: Grant Investigator, Research support. L. A. Jackson, Novartis: Grant Investigator, Research support. R. K. Zimmerman, sanofi pasteur: Grant Investigator, Research support. Pfizer: Grant Investigator, Research support. Merck: Grant Investigator, Research support. M. P. Nowalk, Merck: Grant Investigator, Research support. Pfizer: Grant Investigator, Research support. M. R. Griffin, MedImmune: Grant Investigator, Research support. H. K. Talbot, sanofi pasteur: Investigator, Research grant. Gilead: Investigator, Research grant. MedImmune: Investigator, Research grant. Vaxinnate: Safety Board, none. Seqirus: Safety Board, none. J. J. Treanor, Novartis: Board Member and Consultant, Consulting fee.

scholarly journals Relative Effectiveness of Adjuvanted Trivalent Inactivated Influenza Vaccine Versus Egg-derived Quadrivalent Inactivated Influenza Vaccines and High-dose Trivalent Influenza Vaccine in Preventing Influenza-related Medical Encounters in US Adults ≥ 65 Years During the 2017–2018 and 2018–2019 Influenza Seasons

2021 ◽  
Author(s):  
Constantina Boikos ◽  
Lauren Fischer ◽  
Dan O’Brien ◽  
Joe Vasey ◽  
Gregg C Sylvester ◽  
...  
Keyword(s):  
Influenza Vaccine ◽  
Relative Effectiveness ◽  
The United States ◽  
Geographic Region ◽  
Influenza Vaccines ◽  
High Dose ◽  
Large Dataset ◽  
Medical Claims ◽  
Trivalent Influenza Vaccine ◽  
Race Ethnicity

Abstract Background The effectiveness of standard, egg-derived quadrivalent influenza vaccines (IIV4) may be reduced in adults ≥65 years of age, largely because of immunosenescence. An MF59-adjuvanted trivalent influenza vaccine (aIIV3) and a high-dose trivalent influenza vaccine (HD-IIV3) offer older adults enhanced protection versus standard vaccines. This study compared the relative effectiveness of aIIV3 with IIV4 and HD-IIV3 in preventing influenza-related medical encounters over 2 US influenza seasons. Methods This retrospective cohort study included US patients ≥65 years vaccinated with aIIV3, IIV4, or HD-IIV3. The outcome of interest was the occurrence of influenza-related medical encounters. Data were derived from a large dataset comprising primary and specialty care electronic medical records linked with pharmacy and medical claims. Adjusted odds ratios (OR) were derived from an inverse probability of treatment-weighted sample adjusted for age, sex, race, ethnicity, geographic region, vaccination week, and health status. Relative vaccine effectiveness (rVE) was determined using the formula (% VE = 1 – ORadjusted) × 100. Results In 2017–2018, cohorts included: aIIV3, n = 524 223; IIV4, n = 917 609; and HD-IIV3, n = 3 377 860. After adjustment, 2017–2018 rVE of aIIV3 versus IIV4 was 18.2 (95% confidence interval [CI], 15.8–20.5); aIIV3 vs. HD-IIV3 was 7.7 (95% CI, 2.3–12.8). In 2018–2019, cohorts included: aIIV3, n = 1 031 145; IIV4, n = 915 380; HD-IIV3, n = 3 809 601, with adjusted rVEs of aIIV3 versus IIV4 of 27.8 (95% CI, 25.7–29.9) and vs. HD-IIV3 of 6.9 (95% CI, 3.1–10.6). Conclusion In the 2017–2018 and 2018–2019 influenza seasons in the United States, aIIV3 demonstrated greater reduction in influenza-related medical encounters than IIV4 and HD-IIV3 in adults ≥65 years.

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