Spontaneous increase in influenza vaccination rate among healthcare workers during the season of pandemic influenza at Japanese teaching hospital

Background:  

Influenza is a respiratory pathogen to which healthcare workers (HCWs) are at risk of exposure. If infected, HCWs may contribute to nosocomial spread of the virus to patients. In addition to droplet isolation precautions for patients with influenza, another important preventative measure is influenza vaccination for HCWs. Vaccination for HCWs may prevent transmission of influenza to patients, reduces the risk of spread among HCWs, and creates herd immunity. The vaccination rate among HCWs however is poor and continues to be a challenge. Mandatory vaccination programs for HCWs have been implemented in some hospitals in the United States however some HCWs cite religious, philosophical, medical, or other reasons for refusing vaccination. 

Objective:  

To examine the seasonal and novel H1N1 influenza vaccination rates of HCWs during the 2009 influenza season at a Japanese teaching hospital and compare to vaccination rates during the prior 4 years (2005 – 2008).

Methods:

Influenza vaccination rates from 2005-2009 among HCWs at a 550-bed teaching hospital in Sapporo, Japan were reviewed. The annual vaccination rate and vaccination rates by HCW subgroups, including physicians, nurses, paramedical staffs, and office workers were assessed using student t-test for comparison. Rates of seasonal and H1N1 influenza vaccination for 2009 were also compared to each other and by HCW subgroup.

Results:  

The seasonal influenza vaccination rate among HCWs from 2005-2008 has ranged from 63.3% to 78.3%. In 2009, the seasonal influenza vaccination rate of all HCWs was 79.6% (1153/1449) .The 2009 seasonal vaccination rate among physicians was the lowest (64.5%; 147/228) compared to other HCWs (P<0.001). The H1N1 influenza vaccination rate among all HCWs in 2009 was 92.9%, higher than prior seasonal vaccination rates over the past 5 years (P <0.001). The H1N1 vaccination rate among physicians was low compared to other HCWs (89.5%; 204/228) however no statistical significance was observed. 

Conclusions:

Seasonal influenza vaccination rates among HCWs increased over the last 5 years in this Japanese teaching hospital; however the rate remained suboptimal. Among subgroups of HCWs in 2009, the influenza vaccination rate was the lowest for physicians. The reason for this is unclear.  The H1N1 vaccination rate among HCWs was significantly higher, without mandatory vaccination. This was presumably due to widespread public attention to the H1N1 influenza pandemic that year. Despite improvements in the influenza vaccination rate in 2009, new interventions may be required to maintain higher rates, especially among physicians.  Further assessment of the influenza vaccination rate among HCWs and the reasons for declining the vaccine is needed to evaluate the use of interventions such as a mandatory vaccination program in Japan.