Problems with this year's flu shot have contributed to a bad season.

The perceived effectiveness of a flu vaccination is a much bigger factor in convincing a healthcare worker’s decision to get a flu shot than trying to impress concerns for residents, new research suggests.

The subject of mandatory flu vaccines is a touchy one for many nursing home workers, but new research finds that employers that tout the shot’s effectiveness are more likely to have vaccinated employees.

In a review of 13 existing studies, researchers in the Netherlands found that top factors that led to a greater-than-double increase in flu vaccination included knowing the vaccine is effective; a willingness to prevent the spread of the flu virus; a belief that the virus is highly contagious; and that prevention is important.

Top factors least likely to influence a worker’s motivation to get vaccinated include having direct patient contact; willingness to protect either themselves or patients at risk of complications if they caught the flu; and previous experience with having the flu.

“Influenza vaccination will only be successful in [healthcare workers] if they are properly educated and if the vaccine is easily accessible,” lead researcher Dr. Giedre Gefenaite, Ph.D., said.

The study was published March 7 in Occupational and Environmental Medicine.