Universal Employee Influenza Vaccination Decreases Employee Sick Days

Study results presented at IDWeek 2012 show that requiring flu vaccination for all employees at a large health care facility resulted in a significant drop in the employee absence rate during flu season.

A Denver hospital saw sick days among employees dip after it mandated flu vaccinations for everyone who worked at the facility, according to study results presented at IDWeek 2012, the first joint annual meeting of the Infectious Diseases Society of America (ISDSA), Society for Healthcare Epidemiology of America (SHEA), HIV Medicine Association (HIVMA), and Pediatric Infectious Diseases Society (PIDS).

Hospital employee absences are typically higher during flu season and it is estimated that 25% of health care workers contract influenza every year, said lead researcher Heather Young, MD, of the Denver Health Medical Center. Noting that seasonal influenza is highly contagious and spreads quickly in communities and among the workforce, Young said the study attempted to find out whether universal flu vaccinations would lead to hospital employees calling in sick less often.

For the 2011-2012 flu season, the Denver Health Medical Center allied with Denver Children’s Hospital and the University of Colorado Hospital to require universal flu vaccinations for all employees, residents, contractors, students, and volunteers, Young said. At the end of the flu season, researchers compared their most recent data after the mandate began to estimated data from 2006 to 2007, when flu activity was similar among the adult population, she said.

To encourage wide-spread participation in the campaign, the hospital held clinics over two months and emphasized the safety of the vaccine, Young said. Similar to a handful of other hospitals that have adopted a universal flu vaccination policy, employees could opt out for medical or religious reasons. Those who did at Young’s facility were required to wear masks while on the job and within three feet of a patient.

The real-life application of the surgical masks for employees who opted out posed a few challenges, Young said in an interview after her presentation. Supervisors were given a list of employees who needed to wear masks and the bosses were expected to enforce compliance. In addition, some employees who received vaccinations worried that unvaccinated employees placed them at risk of contracting influenza, she said.

Despite some challenges, the campaign succeeded in vaccinating all but about 80 people who declined the vaccine, Young said. And the data revealed that the universal influenza vaccination policy was associated with decreased employee sick calls in years of comparable influenza activity, Young said.

The influenza vaccination rate was 48% among 4,527 employees in 2006-2007 and 98% of roughly 5,500 employees in 2011-2012. The results showed the mean clinical employee absence rate per 100 employees dropped after the mandate was implemented in 2011, from 9.14 absences to 6.15.

Sick and vacation days are lumped together at the Denver hospital, so it’s possible that employees with a prolonged illness would use all sick days and then cover further days off from illness with vacation time, said Young, commenting on study limitations. Also, the data only covered mild flu seasons and did not evaluate the effect on employee absences during times of high flu activity. “We anticipate that the effect would have been even larger than we demonstrated,” Young said. The universal vaccination policy is still in place and is expected to be required for several more years, she said.