Seasonal and 2009 Influenza A (H1N1) Vaccination among Single General Acute Care Hospital Employees in California, 2009-2010

Background: Healthcare personnel (HCP) are an important source of transmission of the influenza virus; however, their influenza vaccination rates remain unacceptably low.  One strategy to increase compliance is to require HCP to sign a declination statement if they decline to be vaccinated.  In 2006 California became the first state to mandate that general acute care hospitals offer free influenza vaccination to all employees and require written declination; the impact of this mandate has not been assessed.

Objective: To evaluate influenza vaccination in general acute care HCP in California during the 2009-2010 season and assess the impact of mandatory written declination.

Methods: Hospitals submitted influenza vaccination surveillance reports to the California Department of Public Health for the 2009-2010 season.  Calculations included mean hospital-specific vaccination and declination percentages.  Strategies used by hospitals to increase influenza vaccination in HCP were assessed using a web-based survey.  Data on non-employee HCP were excluded due to inconsistencies in definitions used.  Hospitals reporting under a multi-hospital license and not individually also were excluded from analysis.

Results: The mean seasonal influenza and 2009 influenza A (H1N1) vaccination percentages among employees in single hospitals were 63% and 55%, respectively.  Large (205 or more licensed beds) hospitals and pediatric hospitals had significantly higher vaccination percentages for both seasonal influenza and 2009 influenza A (H1N1) (p<0.05).  The mean seasonal influenza and 2009 influenza A (H1N1) declination percentages were 24% and 28%, respectively.  Sixty-three percent (n=194) of reporting hospitals met the Healthy People 2010 target of 60% seasonal influenza vaccination in hospital employees.  Higher performing hospitals were associated with vaccination campaigns that included free, available vaccine to all HCP, mobile vaccination carts, and mandatory educational programs.

Conclusions: Mean hospital-specific percentages for both seasonal influenza and 2009 influenza A (H1N1) vaccines were higher than published national estimates during the 2009-2010 influenza season.  However, the vaccination percentages for 2009 influenza A (H1N1) were lower than seasonal influenza and may have resulted from a shortage of supply early in the season and lack of confidence in the safety of the vaccine.  Large and pediatric hospitals may have resources to implement more effective influenza vaccination campaigns.  Barriers to collecting and reporting influenza vaccination data among non-employee HCP must be addressed.  Finally, mandatory written declination alone did not markedly improve vaccination percentages among hospital employees in California.  The use of mandatory vaccination and/or participation policies should be considered.