181 The Impact of Single Versus Double Vaccination Against Influenza and/or Pneumococcal on the Incidence and Frequency of Acute Heart Failure Exacerbations in a Cohort of Patients With Chronic Heart Failure

Abstract

In Australia, annual Influenza and 5-yearly Pneumococcal vaccinations are provided for free to high-risk patients, including those with chronic cardiac conditions, as a means to prevent infection, a recognised trigger for cardiovascular events. Our aim was to assess the impact of single versus double vaccination against influenza and/or pneumococcal on the incidence and frequency of hospitalisation for acute decompensated heart failure (ADHF). We examined consecutive patients with LVEF <50% attending the outpatient HF clinic at Blacktown Hospital between 2015-2018 whose vaccination status for influenza and pneumococcal was verified with their general practitioner. They were followed up for subsequent hospital presentations for ADHF for 12 months post-vaccination. Of the 190 participants (67±15 years; 37% female) examined over four years from 2015-2018, 30% received annual influenza vaccination only, 8% pneumococcal vaccination only, 16% received both and 45% received no vaccination. There was no significant reduction in the incidence or frequency of ADHF within 1 year of vaccination for those who received a single vaccination or both in any year. However, patients who received no vaccination at all had significantly reduced number of ADHF hospitalisations than those who received one or more vaccinations (0.59 vs 0.45, p=0.048). Double versus single vaccination against influenza and/or pneumococcal did not demonstrate a clear reduction in incidence or number of hospitalisations for ADHF. Reduced number of exacerbations amongst patients who received no vaccination may reflect user bias, in that patients with less stable disease are more likely to be encouraged to undergo vaccination.