Do Patients Benefit from Healthcare Providers' Influenza Vaccination?

Although influenza vaccination is recommended for healthcare providers (HCPs) in the U.S. and many other countries, whether it benefits patients remains controversial. The debate stems in part from the quality of evidence in previous studies.

To rectify this situation, researchers at the CDC conducted a review of randomized, controlled trials, cohort studies, and case-control studies published between January 1948 and June 2012 that reported on the association between influenza vaccination of HCPs and morbidity or mortality among patients of healthcare facilities. They evaluated evidence quality using the Grading of Recommendations Assessment, Development and Evaluation system, a methodology employed by more than 60 organizations worldwide. Out of 8790 articles identified by the literature search, only 8 (4 cluster-randomized trials and 4 observational studies) met the authors' inclusion criteria.

In the cluster-randomized trials, HCP vaccination was associated with a 29% (95% confidence interval, 15%–41%) reduction in all-cause mortality and a 42% (95% CI, 27%–54%) reduction in influenza-like illness among patients. Results of the observational studies also showed HCP influenza vaccination to be associated with decreased risk for influenza-like illness in patients. However, the quality of evidence from the randomized trials was only moderate for the effect of HCP vaccination on reducing mortality among patients and was low for reducing influenza-like illness. In addition, the quality of evidence from the observational studies for mortality and influenza-like illness was very low.