Determinants of influenza vaccination uptake among health workers in Madrid: a mixed-methods study

Background

Influenza vaccination uptake among healthcare workers (HCWs) remains suboptimal despite its importance for patient safety. Evidence on behavioural and organisational determinants in Madrid, Spain is limited. This study aimed to identify factors associated with uptake and explore underlying perceptions.

Methods

A cross-sectional online survey was conducted among HCWs of the Madrid Regional Health Service (December 2025). The questionnaire captured demographics, vaccination history, knowledge, attitudes and access. Descriptive and multivariate analyses, including logistic regression, were performed using SPSS. Open-ended responses were analysed using qualitative content analysis.

Results

A total of 6.145 HCWs participated; 87.3% reported being vaccinated or intending to vaccinate. Non-vaccination was more frequent among younger professionals, non-clinical staff and those outside hospitals. In multivariate analysis, administrative staff (OR 4.09; 95% CI 3.06–5.47), nursing assistants (OR 2.53; 95% CI 1.80–3.56) and younger age were associated with non-vaccination. Lack of information (OR 1.72; 95% CI 1.26–2.35) and social media use (OR 1.39; 95% CI 1.11–1.73) increased risk, while workplace campaigns were protective. Motivations for vaccination were mainly related to protecting others and personal health, whereas non-vaccination was driven by concerns about adverse effects, low perceived need and distrust in vaccine effectiveness. Qualitative findings highlighted information fatigue, demand for transparency and resistance to mandatory approaches. Suggested improvements included tailored communication, improved accessibility and trust-building strategies.

Conclusions

Vaccination uptake among HCWs is influenced by professional profile, information sources and perceptions. Interventions should prioritise tailored communication, strengthen institutional trust and target groups with lower uptake.

Key messages

• Vaccination uptake is shaped by professional profile, risk perception and information sources, with persistent gaps in specific staff groups.

• Organisational communication and trust in evidence are critical levers; qualitative insights highlight barriers beyond access alone.