NICHOLAS BAKALAR writes in the NY Times:
The flu vaccine is far from 100 percent effective, but researchers have calculated that over the past six years it has prevented millions of illnesses and tens of thousands of hospitalizations.
The analysis, from the Centers for Disease Control and Prevention, was published in the journal PLoS One. Using national surveillance data, the researchers estimated the number of cases and hospitalizations in each flu season from 2005-6 through 2010-11. Then, accounting for year-to-year variations in vaccine efficacy, vaccine coverage and disease occurrence, they calculated the number of cases and hospitalizations that were avoided by vaccination. More.