Prevention of Cardiovascular Diseases with Standard-Dose Quadrivalent Influenza Vaccine in People Aged ≥50 Years in Australia During the 2017 A/H3N2 Epidemic

<b>Background:</b> In Australia, 2017 was a severe A/H3N2 season and, therefore, we estimated the effectiveness of standard-dose quadrivalent influenza vaccine in preventing hospitalization for cardiovascular disease (CVD) among New South Wales (NSW) residents aged ≥50 years. <b>Me...

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Main Authors: Zubair Akhtar, Aye M. Moa, Timothy C. Tan, Ole Fröbert, Robert Menzies, C. Raina MacIntyre
Format: Article
Language:English
Published: MDPI AG 2025-04-01
Series:Vaccines
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Online Access:https://www.mdpi.com/2076-393X/13/4/407
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author Zubair Akhtar
Aye M. Moa
Timothy C. Tan
Ole Fröbert
Robert Menzies
C. Raina MacIntyre
author_facet Zubair Akhtar
Aye M. Moa
Timothy C. Tan
Ole Fröbert
Robert Menzies
C. Raina MacIntyre
author_sort Zubair Akhtar
collection DOAJ
description <b>Background:</b> In Australia, 2017 was a severe A/H3N2 season and, therefore, we estimated the effectiveness of standard-dose quadrivalent influenza vaccine in preventing hospitalization for cardiovascular disease (CVD) among New South Wales (NSW) residents aged ≥50 years. <b>Methods:</b> We conducted a nested, matched case–control study within the 45 and Up study, linking data from the Australian Immunization Register, NSW Admitted Patient Data Collection and Pharmaceutical Benefits Schedule. Cases were individuals hospitalized for CVD and controls were those who were hospitalized for gastrointestinal diseases. The two groups were balanced using 1:1 propensity score matching based on age group (50–64, 65–74, 75–84, and ≥85 years) and sex. After adjusting for confounders (smoking, body mass index and income), we calculated the adjusted odds ratio (aOR) for vaccination during the season using multivariable logistic regression. E-values were estimated to assess residual confounding. Vaccine effectiveness (VE) was calculated as (1 − aOR) × 100. <b>Results:</b> There were 10,445 (4452 cases and 5993 controls) study participants. After matching, 8904 (85.2%) were retained with a mean age of 76.4 ± 10.4 years and 58.3% men. Following adjustment for confounders, the aOR of averting a CVD hospitalization was 0.15 (95% CI: 0.13 to 0.17; <i>p</i> < 0.001). The estimated VE against CVD hospitalization was 85% (95% CI: 83 to 87). We found an E-value of 12.82, indicating strong evidence of minimal residual confounding. <b>Conclusions:</b> In the severe 2017 influenza A/H3N2 season in Australia, we observed a high VE in preventing cardiovascular hospitalization despite a low VE against influenza infection prevention. Improving vaccine uptake may reduce cardiovascular burden.
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spelling doaj-art-4740820835f5417da28d11944d0dfd5b2025-08-20T02:18:10ZengMDPI AGVaccines2076-393X2025-04-0113440710.3390/vaccines13040407Prevention of Cardiovascular Diseases with Standard-Dose Quadrivalent Influenza Vaccine in People Aged ≥50 Years in Australia During the 2017 A/H3N2 EpidemicZubair Akhtar0Aye M. Moa1Timothy C. Tan2Ole Fröbert3Robert Menzies4C. Raina MacIntyre5Biosecurity Program, The Kirby Institute, Faculty of Medicine and Health, UNSW, Sydney, NSW 2033, AustraliaBiosecurity Program, The Kirby Institute, Faculty of Medicine and Health, UNSW, Sydney, NSW 2033, AustraliaDepartment of Cardiology, Blacktown Hospital, University of Western Sydney, Blacktown, NSW 2148, AustraliaDepartment of Cardiology, Faculty of Health, Örebro University, 701 82 Örebro, SwedenSanofi, ANZ, Sydney, NSW 2133, AustraliaBiosecurity Program, The Kirby Institute, Faculty of Medicine and Health, UNSW, Sydney, NSW 2033, Australia<b>Background:</b> In Australia, 2017 was a severe A/H3N2 season and, therefore, we estimated the effectiveness of standard-dose quadrivalent influenza vaccine in preventing hospitalization for cardiovascular disease (CVD) among New South Wales (NSW) residents aged ≥50 years. <b>Methods:</b> We conducted a nested, matched case–control study within the 45 and Up study, linking data from the Australian Immunization Register, NSW Admitted Patient Data Collection and Pharmaceutical Benefits Schedule. Cases were individuals hospitalized for CVD and controls were those who were hospitalized for gastrointestinal diseases. The two groups were balanced using 1:1 propensity score matching based on age group (50–64, 65–74, 75–84, and ≥85 years) and sex. After adjusting for confounders (smoking, body mass index and income), we calculated the adjusted odds ratio (aOR) for vaccination during the season using multivariable logistic regression. E-values were estimated to assess residual confounding. Vaccine effectiveness (VE) was calculated as (1 − aOR) × 100. <b>Results:</b> There were 10,445 (4452 cases and 5993 controls) study participants. After matching, 8904 (85.2%) were retained with a mean age of 76.4 ± 10.4 years and 58.3% men. Following adjustment for confounders, the aOR of averting a CVD hospitalization was 0.15 (95% CI: 0.13 to 0.17; <i>p</i> < 0.001). The estimated VE against CVD hospitalization was 85% (95% CI: 83 to 87). We found an E-value of 12.82, indicating strong evidence of minimal residual confounding. <b>Conclusions:</b> In the severe 2017 influenza A/H3N2 season in Australia, we observed a high VE in preventing cardiovascular hospitalization despite a low VE against influenza infection prevention. Improving vaccine uptake may reduce cardiovascular burden.https://www.mdpi.com/2076-393X/13/4/407influenza vaccinationcardiovascular disease (CVD)hospitalizationvaccine effectivenesspropensity score matching
spellingShingle Zubair Akhtar
Aye M. Moa
Timothy C. Tan
Ole Fröbert
Robert Menzies
C. Raina MacIntyre
Prevention of Cardiovascular Diseases with Standard-Dose Quadrivalent Influenza Vaccine in People Aged ≥50 Years in Australia During the 2017 A/H3N2 Epidemic
Vaccines
influenza vaccination
cardiovascular disease (CVD)
hospitalization
vaccine effectiveness
propensity score matching
title Prevention of Cardiovascular Diseases with Standard-Dose Quadrivalent Influenza Vaccine in People Aged ≥50 Years in Australia During the 2017 A/H3N2 Epidemic
title_full Prevention of Cardiovascular Diseases with Standard-Dose Quadrivalent Influenza Vaccine in People Aged ≥50 Years in Australia During the 2017 A/H3N2 Epidemic
title_fullStr Prevention of Cardiovascular Diseases with Standard-Dose Quadrivalent Influenza Vaccine in People Aged ≥50 Years in Australia During the 2017 A/H3N2 Epidemic
title_full_unstemmed Prevention of Cardiovascular Diseases with Standard-Dose Quadrivalent Influenza Vaccine in People Aged ≥50 Years in Australia During the 2017 A/H3N2 Epidemic
title_short Prevention of Cardiovascular Diseases with Standard-Dose Quadrivalent Influenza Vaccine in People Aged ≥50 Years in Australia During the 2017 A/H3N2 Epidemic
title_sort prevention of cardiovascular diseases with standard dose quadrivalent influenza vaccine in people aged ≥50 years in australia during the 2017 a h3n2 epidemic
topic influenza vaccination
cardiovascular disease (CVD)
hospitalization
vaccine effectiveness
propensity score matching
url https://www.mdpi.com/2076-393X/13/4/407
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