Thomas, et al. (2010) sought to identify studies of influenza vaccination of healthcare workers and influenza in elderly residents in long-term care facilities. The researchers searched seven electronic databases for randomized controlled trials (RCTs) and non-RCTs. Two reviewers independently extracted data and assessed trial quality. Their findings are published in the journal Vaccine.
The researchers report that key outcomes are serologically proven influenza, pneumonia, and deaths from pneumonia, and pooled data from three C-RCTs showed no effect. Pooled data from three C-RCTs showed lower resident all-cause mortality, but because influenza constituted less than 10 percent of all deaths even in epidemic years, the researchers say they question the appropriateness of this outcome measure. Pooled data from three C-RCTs showed vaccination of healthcare workers reduced influenza-like illness and data from one C-RCT that HCW vaccination reduced GP consultations for influenza-like illness, but because influenza constitutes less than 25 percent of influenza-like illness and they did not show that healthcare worker influenza vaccination reduced serologically proven influenza, the researchers say they question whether this effect is due to confounding.
Reference: Thomas RE, Jefferson T and Lasserson TJ. Influenza vaccination for healthcare workers who work with the elderly: Systematic review. Vaccine. Oct. 10, 2010. doi:10.1016/j.vaccine.2010.09.085