How Effective is the Flu Vaccine?

As one of the worst influenza seasons in recent years is in full swing, you may be noticing some friends, loved ones, or even yourself, who received a flu vaccination but still became ill with the influenza virus this flu season. You may be asking yourself, does the flu shot work? Why should I get the flu vaccine if the flu vaccine is not effective against protecting against the influenza infection?

There are several ways that the medical community measures the effectiveness of the flu vaccine. According to the CDC:

How do we measure how well influenza vaccines work?

Two types of studies are used to determine how well influenza vaccines work. The first type of study is called a randomized control trial (RCT). In a RCT, volunteers are assigned randomly to either a group that receives vaccine or a group that receives a placebo (e.g., a shot of saline), and vaccine efficacy is measured by comparing the frequency of influenza illness in the vaccinated and the unvaccinated groups. RCTs are required before a new vaccine is licensed for routine use by a national regulatory authority, such as the Food and Drug Administration (FDA) in the United States. The second type of study is called an observational study. In observational studies the study participants make their own decisions about whether or not to be vaccinated. In this type of study, vaccine effectiveness is measured by comparing the frequency of influenza illness in the vaccinated and unvaccinated groups, usually with adjustment for factors (like presence of chronic medical conditions) that may vary between the groups.

What is ‘vaccine effectiveness’?

Vaccine effectiveness is a measure of how well influenza vaccines work to protect against influenza infection and illness when they are used in routine circumstances in the community, and not specifically in a RCT. Effectiveness represents the percentage reduction in the frequency of influenza infections among people vaccinated compared with the frequency among those who were not vaccinated, assuming that the vaccine is the cause of this reduction. These studies are conducted in community settings, and researchers have no control over those who choose to be vaccinated or not.

No vaccine can offer 100% effective protection against infection. However, there is no doubt, that receiving the flu vaccine does increase your chances of remaining influenza free during cold and flu season. It is important to not let one or two cases of individuals who were vaccinated but contracted the influenza virus outshine all the individuals who were protected. Pre book your flu vaccine now with Express Medical Supplies and be prepared for the next flu season!

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