“…Interventions such as education, incentives, easy access, and no cost vaccines have resulted in modest improvements in influenza vaccination rates (Hofmann, Ferracin, Marsh, & Dumas, 2006). Several more rigorous interventions to increase HCP influenza vaccination rates including signed declinations, mandatory masks for unvaccinated HCP, confirmation of vaccination, or declination with unpaid leave for nonadherers are currently being tested (Borlaug, Newman, Pfister, & Davis, 2007;National Foundation for Infectious Diseases, 2008;Polgreen et al, 2008;Ribner et al, 2008). Unfortunately, institutions in which a large percentage of the workforce is represented by one or more labor unions may be hesitant to or prohibited from enforcing such measures if vaccination requirements are not included in current collective bargaining agreements.…”