Work

Assessing factors associated with one-year antibody waning in participants with repeated influenza vaccinations: A six-year cohort study

Year: 2025

Type: article

Abstract: BACKGROUND: The long-term effects of host factors on vaccine-induced immune responses have been widely studied, but limited research has explored the waning of antibody levels after repeated influenza vaccinations in longitudinal settings. METHODS: This study included 330 participants (584 observations), who received the standard-dose influenza vaccine across multiple seasons (≥2) from 2016 to 2022. Host demographics were collected prospectively, and serum samples were obtained pre- and post-vaccination each season. Linear mixed-effects models using restricted maximum likelihood (REML) were applied to evaluate waning scores, defined as the rate of decline in hemagglutination inhibition (HAI) composite scores, while accounting for demographic factors. RESULTS: Higher BMI was significantly associated with greater antibody decline in the teenager subgroup, whereas no significant association was observed in adults or the elderly. In teenagers, age was negatively associated with antibody decline, whereas in adults (19-64 years), age was positively associated. Higher post-vaccination titers and greater pre-post vaccination boost scores were linked to increased antibody waning across all age groups, with significant effects observed in teenagers and adults but not the elderly. The differences by study influenza season influenced antibody waning in adults and the overall cohort but showed no significant effect in teenagers or the elderly (65+ years). Sex was not significantly associated with antibody waning in any age group. CONCLUSIONS: This study highlights multiple factors, including age, BMI, vaccination history, and immune response characteristics, that contribute to the waning of antibodies after repeated influenza vaccinations. These findings underscore the importance of personalized vaccination strategies to maintain long-term immunity and enhance vaccine effectiveness.

Source: Vaccine

DOI: 10.1016/j.vaccine.2025.127904