You have a shortage of doses. Here's why.
Many of us have recently gotten the COVID-19 vaccine or are waiting to get it. With that in mind, one of our listeners wrote in to ask whether you should say you're getting a “dose” of the vaccine or a “dosage” of the vaccine. She mentioned that Governor Cuomo of New York often refers to the shortage of “dosages” for his state, and she wondered if that usage was correct.
To get a precise answer, we turned to the American Medical Association Manual of Style. Here’s its take:
A “dose” refers to the quantity of medicine that is administered at one time. So you could say you are getting a “dose” of the COVID vaccine or that there’s been a shortage of “doses.”
“Dosage,” in contrast, implies a regimen of medicine given over hours or days. It’s usually expressed as a quantity per unit of time. Here are some examples.
Let’s say you injured your knee. Your doctor might prescribe an 800 mg/day dosage of ibuprofen. That means you’d take one 200 mg dose four times per day.
Or let’s say you had a puppy with heartworm. Your vet might prescribe a 20 mg/day dosage of doxycycline, and you’d give her one 10 mg dose in the morning and one at night. (Hopefully, you’d hide it in a treat so she’d actually swallowed it!)
By the way, the word “dose” comes from the medieval Latin “dosis.” That comes from the ancient Greek word “dósis,” meaning “a portion prescribed”— literally, “a giving.” And “dósis” can be traced all the way back to the earliest days of the English language, to what we call Proto-Indo-European. There’s a root word in that language which is “do-,” meaning “to give.”
We see that root in other words related to the act of giving, such as “donor,” “donate,” “pardon,” “dowry,” and “endow.”
Use “dose” when you’re referring to one quantity of medicine you take at one time. Use “dosage” when referring a course of medicine you take over time.
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