Influenza Vaccination Enhances HAI Titers in Individuals with Hypertension: A Retrospective Comorbidity Analysis

BackgroundHypertension (HTN), a chronic condition characterized by low grade inflammation, may influence vaccine induced immune responses. However, the impact of HTN on influenza vaccine immunogenicity remains unclear. MethodsIn a retrospective analysis, 206 adults who received the 2022-2023 quadrivalent inactivated influenza vaccine (Fluzone) were enrolled. Among them, 33 self reported HTN and 56 non HTN individuals were selected as a matched case control group based on age, sex, and BMI. Hemagglutination inhibition (HAI) titers were measured pre and 28 days post vaccination. A subset (HTN: n=6; non HTN: n=9) previously vaccinated with SARS CoV2 mRNA vaccines was assessed for neutralizing antibody titers. ResultsAdults with HTN exhibited significantly higher post vaccination HAI GMTs for A/H1N1 (93 vs. 27) and B/Yamagata (160 vs. 66) compared to non HTN controls. Fold change in A/H1N1 titers was significantly greater in HTN adults (8.7 vs. 2.4; p < 0.01). Elderly HTN participants had higher GMTs for A/H1N1 (46 vs. 27) and A/H3N2 (56 vs. 24). No significant differences were observed in SARS CoV2 neutralization titers. ConclusionsHypertension was associated with robust HAI antibody responses to influenza vaccination, potentially due to the chronic low grade inflammation characteristic of HTN, suggesting that this inflammatory state might augment vaccine induced immunity. However, hypertensive status had no significant impact on SARS CoV2 neutralizing antibody levels.