“Vaccines often consist of an attenuated virus, which is able to stimulate a person’s immune system without causing significant harm.”

According to the sentence above, what is the best definition of attenuate?

Check your answer!

Choice A - To abridge something or decrease its duration
Choice B - To stretch something out or increase its duration
Choice C - To lessen the power or severity of something
Choice D - To increase the power or strength of something


Attenuate (verb) – to lessen the power, effect, amount, or severity of; to make thinner

Attenuated (adjective) – lessened in power, effect, amount, or severity

GRE pro tips:

Attenuate is derived from the Latin ad, meaning “to,” and tenuis means “thin.” Today, the verb attenuate usually means to lessen in power, effect, amount, or severity. In medicine, for instance, vaccines commonly consist of attenuated viruses – or viruses that have been made weaker by removing their ability to grow and replicate in host cells. Such viruses are capable of stimulating a person’s immune response to the “normal”/un-attenuated virus while not causing significant harm to their host.

Note that attenuated can also literally mean to make something thinner. For example, if you’ve ever studied Gothic architecture, you may recall learning about attenuated spires – they rise to a considerable height, getting increasingly slender as they ascend.

Example sentences:

“Drugs like Tylenol help to attenuate a high fever.”

“In some areas, hunting helps to attenuate deer overpopulation and the risk of deer-related car accidents.”