Covid-19 and influenza vaccine effectiveness against associated hospital admission and death among individuals over 65 years in Norway : A population-based cohort study, 3 October 2022 to 20 June 2023

Copyright © 2023 The Author(s). Published by Elsevier Ltd.. All rights reserved..

BACKGROUND: Co-circulation of SARS-CoV-2 and influenza virus can lead to double epidemics and increased pressure on health systems. To evaluate the effect of both vaccines, we estimated the adjusted vaccine effectiveness (aVE) of influenza and Covid-19 vaccines against related severe disease in the elderly population in Norway during the 2022/2023 season.

METHODS: In this population-based cohort study, we included data from the Emergency preparedness register for Covid-19 (Beredt C19) on all individuals ≥ 65 years living in Norway between 3 October 2022 and 20 June 2023. Using Cox-proportional hazard models, we estimated aVE of both influenza and Covid-19 vaccines (bivalent BA.1 and BA.4-5) against associated hospitalisation and death. Vaccine status was included as a time-varying covariate and all models were adjusted for potential confounders, including the other vaccine.

RESULTS: We identified 2,437 influenza-associated hospitalisations and 178 deaths, alongside 5,824 Covid-19-associated hospitalisations and 621 deaths. The aVE was highest in the first three months after receiving either vaccine. Against influenza-associated hospitalisation the aVE was 34 % (26 %-42 %) among 65-79-year-olds and 40 % (30 %-48 %) among ≥ 80-year-olds, and 6.6 % (-64 %-47 %) and 37 % (0.5 %-61 %) against influenza-associated death, respectively. The aVE against Covid-19-associated hospitalisation was 65 % (61 %-69 %) among 65-79-year-olds and 55 % (49 %-60 %) among ≥ 80-year-olds (compared to having received the vaccine ≥ 180 days ago). Similarly, the aVE against Covid-19-associated death was 68 % (48 %-80 %) and 78 % (65 %-86 %), respectively. For Covid-19 we show a reduction in aVE with time since dose.

CONCLUSION: Covid-19 and influenza vaccines reduced the risk of severe disease in the same high-risk population. Ensuring high uptake of both vaccines could thus limit the overall health care burden.

Medienart:

E-Artikel

Erscheinungsjahr:

2024

Erschienen:

2024

Enthalten in:

Zur Gesamtaufnahme - volume:42

Enthalten in:

Vaccine - 42(2024), 3 vom: 25. Jan., Seite 620-628

Sprache:

Englisch

Beteiligte Personen:

Seppälä, Elina [VerfasserIn]
Dahl, Jesper [VerfasserIn]
Veneti, Lamprini [VerfasserIn]
Rydland, Kjersti Margrethe [VerfasserIn]
Klüwer, Birgitte [VerfasserIn]
Rohringer, Andreas [VerfasserIn]
Meijerink, Hinta [VerfasserIn]

Links:

Volltext

Themen:

COVID-19
COVID-19 Vaccines
COVID-19 vaccines
Cohort studies
Death
Hospitalization
Influenza, Human
Influenza Vaccines
Influenza vaccines
Journal Article
Norway
Real-world evidence
Registries
SARS-CoV-2
Vaccine effectiveness
Vaccine efficacy

Anmerkungen:

Date Completed 05.02.2024

Date Revised 05.02.2024

published: Print-Electronic

Citation Status MEDLINE

doi:

10.1016/j.vaccine.2023.12.050

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM366328786