Researchers in the Centers for Disease Control and Prevention in Atlanta used surveillance data collected during the flu season to project the burden of flu in the absence of vaccination compared to the burden with vaccination. By looking at the difference between the two, the researchers estimated the burden of flu averted by vaccination.
In the past, CDC relied on surveys of vaccine coverage and observational studies of vaccine effectiveness that focused on specific populations at specific times to assess and communicate the benefits of vaccination.
The new model provides a more standardized and repeatable way to measure and communicate some of the direct public health benefits of flu vaccination, the CDC said.
The flu season with the greatest benefit of flu vaccination occurred during the 2010-11 season, when flu vaccination averted more than 18.5 percent of potential flu cases. This translates into flu vaccines averting about 5 million flu cases, 2.1 million flu-related medical visits and 40,400 flu-related hospitalizations across all U.S. age groups.
The study authors attributed the significant vaccine benefits in 2010-11 was due to the increase in vaccination coverage among all age groups following the 2009 pandemic.
The season with the lowest number of averted outcomes was 2006-07, when about 1.1 million flu cases were averted, a year with a milder flu season.
The findings were published in the journal Plos One