This FLUNITY-HD pooled analysis of over 466,000 older adults demonstrated that high-dose influenza vaccine provides superior cardiovascular protection compared with standard-dose vaccine. The data support preferential use of high-dose formulations in elderly patients with cardiovascular disease.
Background: The high-dose inactivated influenza vaccine (HD-IIV) has demonstrated superior protection against a range of hospitalization endpoints versus standard-dose inactivated influenza vaccine (SD-IIV), but its effectiveness against specific cardiovascular (CV) outcomes and in those with pre-existing CV disease (CVD) is not well elucidated.Methods: In a prespecified secondary analysis of the FLUNITY-HD individual-level pooled dataset integrating two methodologically harmonized pragmatic, individually randomized trials conducted in Denmark and Spain, we investigated the relative vaccine effectiveness (rVE) of HD-IIV vs. SD-IIV against severe CV outcomes and according to pre-existing CVD among adults aged ≥65 years. Data were primarily obtained from routine healthcare databases, with follow-up from 14 days post-vaccination to May 31 the following year.Results: The pooled dataset encompassed 466,320 individually randomized participants, of whom 107,700 (23.1%) had a history of CVD. H
