Influenza vaccination in healthcare workers; comparison of side effects and preferred route of administration of intradermal versus intramuscular administration.

OBJECTIVE: To explore the nature and severity of side effects and future preference of intradermal versus intramuscular influenza vaccination in healthcare workers. DESIGN: Prospective cohort study. SETTING: Two University Medical Centers in The Netherlands. PARTICIPANTS: Healthcare workers receiving an influenza vaccination. METHODS: Healthcare workers that were vaccinated during the influenza vaccination season of 2012-2013 were approached for participation in a questionnaire study. The questionnaire was divided into two parts. The first part had to be answered directly after vaccination and the second part two weeks after vaccination. The motivation for vaccine uptake, whether or not the HCWs had direct contact with patients and the prevalence and severity of local and systemic side effects of influenza vaccination were explored. In addition, it was assessed how participants experienced the vaccination and which type of administration they preferred for future vaccination. RESULTS: Side effects of vaccination were more prevalent in the intradermal group versus the intramuscular group (56% versus 26%, p<0.001). Local side effects were perceived as more severe in healthcare workers receiving the intradermal vaccine. Directly after vaccination, healthcare workers preferred the intradermal vaccination. Two weeks after vaccination both types of vaccine were equally appreciated. CONCLUSIONS: This study shows that there are significant differences in the nature and severity of side effects upon intramuscular and intradermal influenza vaccination. This difference did not result in a preference among the vaccinated subjects for one type of vaccine.

Determination of factors required to increase uptake of influenza vaccination among hospital-based healthcare workers.

A questionnaire study was performed in all eight University Medical Centers in The Netherlands to determine the predictors of influenza vaccination compliance in hospital-based healthcare workers (HCWs). Demographical, behavioural and organisational determinants were assessed based on behavioural and implementation models. Multivariable regression analysis was applied to assess the independent predictors for influenza vaccine uptake. Age >40 years, the presence of a chronic illness, awareness of personal risk and awareness of risk of infecting patients, trust in the effectiveness of the vaccine to reduce the risk of infecting patients, the HCWs' duty to do no harm and their duty to ensure continuity of care, finding vaccination useful despite the constant flow of visitors and having knowledge of the Health Council's advice, social influence and convenient time for vaccination were all independently associated with vaccine uptake. The accuracy of the prediction model was very high (area under the receiver operating curve: 0.95). Intervention programmes to increase influenza vaccine uptake among HCWs should target the relevant determinants identified in this study.