(250) The Coverage of Influenza Vaccination and Predictors of Not Receiving the Influenza Vaccination in Danish Cancer Patients

Sunday, August 28, 2022

8:00 AM – 1:45 PM CEST

Location: Hall C

Publication Number: 1295

Presenting Author(s)

Lau Amdisen
– Aarhus University and Aarhus University Hospital, Aarhus N, Midtjylland, Denmark

Co-Author(s)

Lars Pedersen, MSc, PhD
– Professor, Department of Clinical Epidemiology, Aarhus University Hospital and Aarhus University, Aarhus, Denmark, Denmark
Niels Abildgaard
– Hematology Research Unit, Department of Hematology, Odense University Hospital and Department of Clinical Research, University of Southern Denmark, Denmark
Christine Stabell Benn
– Bandim Health Project, OPEN, Department of Clinical Research, University of Southern Denmark and Odense University Hospital, Denmark
Mikael Rørth
– Department of Clinical Epidemiology, Department of Clinical Medicine, Aarhus University Hospital, Aarhus University, Denmark
Deirdre Cronin-Fenton
– Department of Clinical Epidemiology, Department of Clinical Medicine, Aarhus University and Aarhus University Hospital, Aarhus, Denmark, Denmark
Signe S�rup
– Department of Clinical Epidemiology, Aarhus University, Aarhus N, Midtjylland, Denmark

Background: Since 2007, influenza vaccination has been free-of-charge for Danish residents aged ≥65 years or persons with acquired immune defects, which may include hematological cancer patients or patients receiving immunosuppressive therapy. In the general Danish population, approx. 94% of persons < 65 years and 50% of persons ≥65 years were influenza unvaccinated.

Objectives: To describe the coverage of influenza vaccination and predictors of not receiving influenza vaccination in Danish cancer patients.

Methods: In this register-based cohort study, we included patients aged ≥18 years registered in the Danish Cancer Registry with a diagnosis of incident cancer from 1/10-2002 to 1/10-2017 and followed for up to five years. Using the Danish national registries, we obtained influenza vaccination status at the end of each influenza season (2007/2008–2017/2018) and data on health, treatment, and demographic and socioeconomic factors. We estimated adjusted prevalence ratios (aPR) and 95% confidence intervals (95%CI) of not receiving influenza vaccination using a modified Poisson approach.

Results: We included 270,645 cancer patients. For all influenza seasons combined, 87% of patients < 65 years and 49% of patients ≥65 years were unvaccinated. Not receiving influenza vaccination in the previous season was associated with non-vaccination in the current season ( < 65 years: aPR=3.00, 95%CI=2.95-3.06; ≥65 years: aPR=5.27, 95%CI=5.21-5.33). Solid tumor patients were more likely to be unvaccinated than hematological cancer patients ( < 65 years: aPR=1.06, 95%CI=1.06-1.07; ≥65 years: aPR=1.06, 95%CI=1.05-1.07). In patients < 65 years, those not receiving medical anti-cancer therapy had higher likelihood of not receiving vaccination compared with patients on immunosuppressive therapy (aPR=1.10, 95%CI=1.10-1.11); no association was found for those ≥65 years (aPR=0.99, 95%CI=0.98-1.00). Those dying in the beginning of the season were more likely to be unvaccinated than those surviving the season ( < 65 years: aPR=1.25, 95%CI= 1.23-1.27; ≥65 years: aPR= 1.97, 95%CI= 1.93-2.00) Sex, cohabitation, origin, educational level, and years since diagnosis did not appear to be important predictors with aPR ranging from 0.97 to 1.04.

Conclusions: The proportion of influenza vaccinated was only slightly higher in cancer patients compared with the general population. Patients with hematological cancer had higher prevalence of vaccination compared with solid tumor patients. In patients < 65 years, immunosuppressive therapy was associated with increased vaccination uptake compared with patients who received no therapy. Our study showed, that non-vaccination in the previous season was the strongest predictor of not receiving influenza vaccination in the current season.