CDC Flu – CWEB.com
The U.S. is experiencing widespread and intense flu activity, and flu activity is likely to continue for several more weeks. Vaccination is our main tool to prevent flu infection. Flu vaccination efforts should continue as long as flu viruses are circulating, but antiviral drugs are the most important tool for flu treatment. Get CDC’s latest updates and guidance on the 2017-2018 flu season.
CDC conducts studies to measure the benefits of seasonal flu vaccination each flu season to help determine how well flu vaccines are working. These vaccine effectiveness (VE) studies regularly assess and confirm the value of flu vaccination as a public health intervention. Study results of vaccine effectiveness can vary based on study design, outcome(s) measured, population studied and the season in which the flu vaccine was studied.
Adjusted vaccine effectiveness estimates for influenza seasons from 2005-2017:
In 2004-05, the flu vaccine was 10 percent effective.
In 2005-06, the flu vaccine was 21 percent effective.
In 2006-07, the flu vaccine was 52 percent effective.
In 2007-08, the flu vaccine was 37 percent effective.
In 2008-09, the flu vaccine was 41 percent effective.
In 2009-10, the flu vaccine was 56 percent effective.
In 2010-11, the flu vaccine was 60 percent effective.
In 2011-12, the flu vaccine was 47 percent effective.
In 2012-13, the flu vaccine was 49 percent effective
In 2013-14, the flu vaccine was 52 percent effective.
In 2014-15, the flu vaccine was 19 percent effective.
In 2015-16, the flu vaccine was 48 percent effective.
In 2016-17, the flu vaccine was 39 percent effective.
CDC has been working with researchers at universities and hospitals since the 2003-2004 flu season to estimate how well flu vaccine works through observational studies using medically attended laboratory-confirmed flu as the outcome. This is the U.S. Flu Vaccine Effectiveness (VE) Network. The U.S. Flu VE Network currently consists of five study sites across the United States that measure the flu vaccine’s effectiveness at preventing outpatient medical visits due to laboratory-confirmed influenza. CDC’s observational studies at U.S. Flu VE Network sites measure outpatient visits* for laboratory-confirmed influenza infections using a highly accurate lab test called rRT-PCR to verify the outcome. These studies compare the odds of vaccination among outpatients with acute respiratory illness and laboratory-confirmed influenza infection to the odds of vaccination among outpatients with acute respiratory illness who test negative for influenza infection.
The overall, adjusted vaccine effectiveness estimates for influenza seasons from 2005-2017 are noted in the chart below. (Estimates are typically adjusted for study site, age, sex, underlying medical conditions, and days from illness onset to enrollment.