Influenza Vaccine Effectiveness in Preventing Admissions With Influenza During the 2014-2015 Influenza Season: A Test-Negative Hospital-Based Study, in the Valencia Hospital Network for the Study of Influenza and Respiratory Viruses Disease, Valencia (Spain)

Introduction Seasonal influenza vaccination is widely recommended for people with risk factors, especially for people who are elderly. However, influenza vaccine effectiveness (IVE) varies year after year because of the variable antigenic composition of the circulating viruses and the vaccine composition. Methods: We summarise the results of IVE and the impact of previous vaccination among subjects 60 years of age and over in a multicentre prospective study in the Valencia Hospital Surveillance Network for the Study of Influenza and Respiratory Viruses Disease (VAHNSI) in Spain. We applied the test-negative design taking laboratory-confirmed influenza as outcome and vaccination status as exposure. Information about potential confounders was obtained from clinical registries or directly from patients. Results: Adjusted IVE was 19% (95% confidence interval (CI): −15 to 43). For patients vaccinated in the current season but not in the two previous seasons, effectiveness was 49% (95% CI: −20 to 78) and for patients vaccinated in the current and any of two previous seasons, effectiveness was 29% (95% CI: −3 to 52). For those patients not vaccinated in the current season but vaccinated in any of the two previous seasons, effectiveness was 53% (95% CI: 8 to 76). Conclusions: Our data show a low vaccine effectiveness for the 2016/17 influenza season.

Download Full-text

Intraseason decline in influenza vaccine effectiveness during the 2016 southern hemisphere influenza season: A test-negative design study and phylogenetic assessment

Vaccine ◽

10.1016/j.vaccine.2019.02.027 ◽

2019 ◽

Vol 37 (19) ◽

pp. 2634-2641 ◽

Cited By ~ 2

Author(s):

Annette K. Regan ◽

James E. Fielding ◽

Monique B. Chilver ◽

Kylie S. Carville ◽

Cara A. Minney-Smith ◽

...

Keyword(s):

Influenza Vaccine ◽

Southern Hemisphere ◽

Influenza Season ◽

Vaccine Effectiveness ◽

Design Study

Download Full-text

Influenza Vaccine Effectiveness Among Children for the 2017–2018 Season

Journal of the Pediatric Infectious Diseases Society ◽

10.1093/jpids/piz077 ◽

2019 ◽

Vol 9 (4) ◽

pp. 468-473 ◽

Cited By ~ 2

Author(s):

Lauren N Powell ◽

Rodolfo E Bégué

Keyword(s):

Influenza Vaccine ◽

Influenza A ◽

Influenza Season ◽

Vaccine Effectiveness ◽

Influenza B ◽

Immunization Registry ◽

Previous Season ◽

Waning Immunity ◽

Small Benefit ◽

Susceptible Populations

Abstract Background The 2017–2018 influenza season was of high severity. Circulating influenza strains change periodically, making it important to determine vaccine effectiveness on an annual basis, especially for susceptible populations. The primary aim of our study was to estimate the effectiveness of the influenza vaccine among children. Secondary aims were to assess the effect of previous season vaccination and intraseasonal waning of immunity. Methods Children 6 months to 17 years of age tested for influenza during the 2017–2018 season were included. Clinical charts were reviewed, and immunization status was confirmed via the Louisiana Immunization Registry. Influenza vaccine effectiveness (IVE) was estimated in a test-negative design by comparing vaccination status of influenza-positive vs influenza-negative cases. Results A total of 3595 children were included, 26% of whom tested positive for influenza, mostly type A (79%); 15% had received an influenza vaccine prior to illness: 8% among the influenza-positive and 17% among influenza-negative cases (P <.0001). IVE for the 2017–2018 influenza season was 52% overall (95% confidence interval, 38%–62%), 49% for influenza A, and 60% for influenza B. While receiving current year (2017–2018) vaccine had the most effect, receiving the previous year (2016–2017) vaccine had a small benefit and no interference. We found no evidence of waning immunity of the vaccine for the 2017–2018 season. Conclusions IVE was moderate for children. Previous year vaccination had a small but significant benefit and there was no evidence of waning immunity in our cohort. Ongoing national and local surveillance is important to understand the benefit of influenza vaccination.

Download Full-text

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

Open Forum Infectious Diseases ◽

10.1093/ofid/ofab604 ◽

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.

Download Full-text

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

Open Forum Infectious Diseases ◽

10.1093/ofid/ofab466.1533 ◽

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)

Download Full-text

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

Clinical Infectious Diseases ◽

10.1093/cid/ciz1244 ◽

2020 ◽

Vol 71 (8) ◽

pp. e368-e376 ◽

Cited By ~ 7

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.

Download Full-text

Influenza vaccine effectiveness during the 2012 influenza season in Victoria, Australia: Influences of waning immunity and vaccine match

Journal of Medical Virology ◽

10.1002/jmv.23847 ◽

2013 ◽

Vol 86 (6) ◽

pp. 1017-1025 ◽

Cited By ~ 40

Author(s):

Sheena G. Sullivan ◽

Naomi Komadina ◽

Kristina Grant ◽

Lauren Jelley ◽

Georgina Papadakis ◽

...

Keyword(s):

Influenza Vaccine ◽

Influenza Season ◽

Vaccine Effectiveness ◽

Waning Immunity

Download Full-text

Influenza vaccine effectiveness for hospital and community patients using control groups with and without non-influenza respiratory viruses detected, Auckland, New Zealand 2014

Vaccine ◽

10.1016/j.vaccine.2015.11.073 ◽

2016 ◽

Vol 34 (4) ◽

pp. 503-509 ◽

Cited By ~ 20

Author(s):

Nevil Pierse ◽

Heath Kelly ◽

Mark G. Thompson ◽

Ange Bissielo ◽

Sarah Radke ◽

...

Keyword(s):

New Zealand ◽

Influenza Vaccine ◽

Respiratory Viruses ◽

Vaccine Effectiveness ◽

Control Groups ◽

Community Patients

Download Full-text

Vaccine effectiveness against influenza-associated hospitalizations among adults, 2018-2019, US Hospitalized Adult Influenza Vaccine Effectiveness Network

The Journal of Infectious Diseases ◽

10.1093/infdis/jiaa772 ◽

2020 ◽

Author(s):

J M Ferdinands ◽

M Gaglani ◽

S Ghamande ◽

E T Martin ◽

D Middleton ◽

...

Keyword(s):

Influenza Vaccine ◽

Influenza A ◽

Influenza Season ◽

Respiratory Illness ◽

Vaccine Effectiveness ◽

H3n2 Virus ◽

Influenza A H1n1 ◽

The Us ◽

Middle Aged Adults ◽

Residual Confounding

Abstract We estimated vaccine effectiveness for prevention of influenza-associated hospitalizations among adults during the 2018-2019 influenza season. Adults admitted with acute respiratory illness to 14 hospitals of the US Hospitalized Adult Influenza Vaccine Effectiveness Network and testing positive for influenza were cases; patients testing negative were controls. Vaccine effectiveness was estimated using logistic regression and inverse probability of treatment weighting. We analyzed data from 2863 patients with mean age of 63 years. Adjusted VE against influenza A(H1N1)pdm09-associated hospitalization was 51% (95%CI 25, 68). Adjusted VE against influenza A(H3N2) virus-associated hospitalization was −2% (95%CI −65, 37) and differed significantly by age, with VE of −130% (95% CI −374, −27) among adults 18 to ≤56 years of age. Although vaccination halved the risk of influenza-A(H1N1)pdm09-associated hospitalizations, it conferred no protection against influenza A(H3N2)-associated hospitalizations. We observed negative VE for young-and middle-aged adults but cannot exclude residual confounding as a potential explanation.

Download Full-text

Effectiveness of influenza vaccine among health care personnel in Thailand, 2018/19 season

European Journal of Public Health ◽

10.1093/eurpub/ckaa165.1096 ◽

2020 ◽

Vol 30 (Supplement_5) ◽

Author(s):

T Eamchotchawalit ◽

P Piyaraj ◽

P Narongdej ◽

S Charoensakulchai ◽

C Chanthowong

Keyword(s):

Health Care ◽

Influenza Vaccine ◽

Influenza Vaccination ◽

Seasonal Influenza ◽

Influenza Season ◽

Influenza Infection ◽

Vaccine Effectiveness ◽

Health Care Personnel ◽

Seasonal Influenza Vaccine ◽

Influenza Like Illness

Abstract Background Influenza vaccination is the most effective way of preventing influenza infections and it is recommended for the entire health care personnel in Thailand. However, the evidence of influenza vaccine effectiveness (VE) among health care personnel is lacking in Thailand. The objective of this study was to estimate influenza vaccine effectiveness (VE) against laboratory confirmed medically attended influenza illness for the 2018/9 season among health care personnel who at risk for influenza infection in Bangkok, the capital of Thailand. Methods Throat swab specimens were collected from patients with influenza-like illness (ILI) presenting to outpatient clinics and tested for influenza virus by RT-PCR, between October 2018 and September 2019. A test-negative case-control design was used to estimate influenza VE against medically-attended laboratory-confirmed influenza in outpatient settings. Cases were influenza-like illness (ILI) patients who tested positive for influenza, and controls were influenza negative patients. Results During the 2018/19 season 373 samples were collected; 57 (15.3%) were positive for influenza, 70.2% A un-subtyped and 29.8% B. Adjusted VE against all influenza viruses for this influenza season was -31.7% (95% confidence interval (CI): -40.2 to 66.4), against influenza A un-subtyped, it was 43.9% (95% CI: -30.6 to 75.9) and against influenza B, it was 52.0% (95% CI: (-73.9 to 86.8). Conclusions The seasonal influenza vaccine was moderately effective against medically attended lab-confirmed influenza infection in health care personnel in Bangkok, Thailand in the 2018-19 influenza season. Key messages The seasonal influenza vaccine was moderately effective against medically attended lab-confirmed influenza infection in health care personnel in Bangkok. Increasing seasonal influenza vaccination among health care personnel in Thailand may decrease medically attended influenza-associated ILI cases in this population.

Download Full-text