Editorial Commentary: Influenza Vaccine: Glass Half Full or Half Empty?

The author discusses the assessment of influenza vaccine effectiveness during the 2010–2011 influenza season, using a nonrandomized, prospectively followed cohort analysis. It reports two findings which includes the rate of polymerase chain reaction–documented influenza illness was not substantially different and influenza vaccination in a previous season may have impacted the effectiveness of the vaccine in the current season.