Influenza vaccination for healthcare workers who work with the elderly: Systematic review

The 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 as influenza constituted less than 10% of all deaths even in epidemic years we question the appropriateness of this outcome measure. Pooled data from three C-RCTs showed vaccination of HCWs reduced ILI and data from one C-RCT that HCW vaccination reduced GP consultations for ILI, but as influenza constitutes less than 25% of ILI and we did not show that HCW influenza vaccination reduced serologically proven influenza we question whether this effect is due to confounding.