A systematic review of mandatory influenza vaccination in healthcare personnel

Context: Influenza is a major cause of patient morbidity. Mandatory influenza vaccination of healthcare personnel (HCP) is increasingly common yet has uncertain clinical impact. This study systematically examines published evidence of the benefits and harm of influenza vaccine mandates.

Evidence acquisition: MEDLINE, Embase, the Cochrane Library, Cumulative Index to Nursing and Allied Health Literature, Science Citation Index Expanded, and Conference Proceedings Citations Index were searched and analyzed in 2013. Studies must have assessed the effect of a requirement of influenza vaccination among HCP for continued employment or clinical practice. Studies were not limited by comparison group, outcome, language, or study design. Two reviewers independently abstracted data and assessed bias risk.

Evidence synthesis: Twelve observational studies were included in the study from 778 citations. Following implementation of a vaccine mandate, vaccination rates increased in all eight studies reporting this outcome, exceeding 94%. Three studies documented increased vaccination rates in hospitals with mandates compared to those without (p<0.001 for all comparisons). Two single-institution studies reported limited, inconclusive results on absenteeism among HCP. No studies reported on clinical outcomes among patients. Medical and religious exemptions and terminations or voluntary resignations were rare.

Conclusions: Evidence from observational studies suggests that a vaccine mandate increases vaccination rates, but evidence on clinical outcomes is lacking. Although challenging, large healthcare employers planning to implement a mandate should develop a strategy to evaluate HCP and patient outcomes. Further studies documenting the impact of HCP influenza vaccination on clinical outcomes would inform decisions on the use of mandatory vaccine policies in HCP.