What is the difference between effectiveness and efficacy

Other factors might include how much disease activity there is in a town or workplace, and whether there are new variants, as there are with SARS-CoV-2, that react differently to a vaccine than the original virus strain.

These two words come up often as journalists report on the multiple studies that have tested how well the vaccines work to prevent COVID An example: Imagine there were people in the vaccine group, and people in the placebo group.

For the best individual protection, you will want to get vaccinated and follow CDC recommendations for wearing a mask, social distancing, staying home when you are sick, and knowing how much virus activity there is in your community. This article was medically reviewed by F. As always, you can thank the English language—and its roots in Latin—for making learning these definitions and connections so, er, fun?

Before we move on, it is important to point out a few reasons why these words are so confusing. The first is that they all, of course, have to do with getting stuff done.

Second, all of these words look really similar to each other. While efficacy and effectiveness may function as synonyms in general usage, they actually have a specific difference in epidemiology, especially when referring to vaccines.

Vaccine efficacy is a measure of how well a vaccine lowers the prevalence of a disease under ideal, controlled conditions. In other words, it is a measure of how well a vaccine prevents the spread of a virus when tested in a research laboratory or highly controlled study. In other words, it is the measure of how well a vaccine prevents the spread of the disease when actually used out in society.

Putting it all together, scientists are interested in the difference between these two measurements because it provides important information about the vaccine that may not be testable in a lab, such as if the vaccine is too expensive or if it is affected by a condition e. Scientists are now keeping a close eye on COVID vaccine distribution and seeing how the vaccine effectiveness compares to the vaccine efficacy.

Regardless of which word we use, one thing is for sure: we all want this pandemic to be over! Home Vaccineswork What is the difference between efficacy and effectiveness? Back to What is the difference between efficacy and effectiveness? Related Content.

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