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. CDC has been working with researchers at universities and hospitals since the flu season to estimate how well flu vaccine works through observational studies using laboratory-confirmed flu as the outcome. CDC uses three networks to estimate vaccine effectiveness: the U. The U.
Biomed Res Int. Effectiveness of seasonal influenza vaccines in the United States during a season with circulation of all three vaccine strains. Chronic medical conditions increase the risk of influenza-related hospitalization and vaccination coverage often is higher among people with chronic medical conditions. Archived from the original on May 27, Bias is an unintended systematic error in the way researchers select study participants, measure outcomes, or analyze data that can lead to inaccurate results. Effectiveness of non-adjuvanted pandemic influenza A vaccines for preventing pandemic influenza acute respiratory illness visits in 4 U. Archived from the original on November 14, The flu vaccine can cause serious side effects, including an allergic reaction, but this is rare.
Two general types of studies are used to determine how well influenza vaccines work: randomized controlled trials and observational studies. These study designs are described below. The first type of study design is called a randomized controlled trial RCT. In a RCT, volunteers are assigned randomly to receive an influenza vaccine or a placebo e. Vaccine efficacy is measured by comparing the frequency of influenza illness in the vaccinated and the unvaccinated placebo groups. The RCT study design minimizes bias that could lead to invalid study results.
Views Read Edit View history. International Drug Price Indicator Guide. Retrieved October 13, A systematic.