How should you capitalize Delta Variant?

I know it’s not the most important question right now, but given how often we speak of the COVID Delta Variant, what’s the right way to capitalize it?

This discussion is not a definitive answer from a grammar expert, but more of a philosophical ramble intended to make you think.

What is the Delta Variant?

In May, the World Health Organization started labelling variants of the COVID-19 virus with Greek letters. Previously, people discussed them according to where they were discovered (for example, the India strain) or with scientific letter-and-number codes regarding their genetic characteristics (B.1.617.2). The geographical designations added stigma to nations that identified new strains, but which might or might not have been their places of origin of these variants. The scientific nomenclature was hard to parse (the first four variants, B.1.1.7, B.1.351, P.1, and B.1.617.2, are tough to keep straight for nonscientists). The international media rapidly adopted the Greek letter convention, since it’s easier to discuss.

The Delta Variant is a particular concern since it multiplies more quickly because infected individuals harbor more virus particles, thus making is far easier to spread. This is one reason why Delta is able to create breakthrough infections even in vaccinated individuals — nearly all such people are able to fight off the virus before it becomes prevalent enough to hospitalize or kill them, but not quickly enough to prevent them from spreading infections to others.

Different publications style “Delta Variant” differently

According to AP Style guide, there’s no need to capitalize delta. Here’s what they had to say in a Q&A format:

QUESTION from Bowling Green, Ohio, on Aug. 06, 2021: Are you sure we shouldn’t capitalize Delta, when mentioning the coronavirus variant? Thanks.

ANSWER: Some styles capitalize it. Others don’t. You can choose which style you prefer. We chose not to capitalize it because letters of the Greek alphabet aren’t capitalized. You could also think of it as the first variant, the second variant, etc.

QUESTION from Providence, Rhode Island, on Aug. 10, 2021: I am seeing the variant delta capitalized in various ways in national and regional publications. Is AP style lowercase d as in “the delta variant”?

ANSWER: Yes, our style is lowercase: the delta variant.

The Washington Post agrees with the AP:

It’s been a week since the Centers for Disease Control and Prevention issued new masking guidance based on evidence that vaccinated people can become infected and transmit the more contagious delta variant to others.

However, other publications disagree. Here’s how it looks in the New York Times:

The vaccines remain highly effective at preventing severe illness and death, but the highly contagious Delta variant and persistent vaccine refusal have taken the country in an unexpected direction.

And CNN also capitalizes Delta:

The Delta variant of Covid-19 is weighing on Southwest Airlines’ bottom line.The carrier said in a regulatory filing Wednesday that customers this month have been booking fewer flights and are increasingly canceling the trips they’ve already booked. 

The CDC and the WHO both capitalize Delta.

So is Delta Variant a proper noun, or isn’t it?

We capitalize proper nouns.

This is why ordinary diseases aren’t capitalized: influenza, chickenpox, malaria, measles, cancer. They represent a variety of different strains and syndromes, and are not specific enough to be considered proper nouns.

Some diseases are rendered in caps because of the origin of the word. The Zika virus was named for the Zika forest in Uganda; Hashimoto’s disease was first described by a Japanese doctor named Hashimoto.

It seems to me that the Delta Variant of COVID-19 is a highly specific disease, worthy of treatment as a proper noun. That’s why I disagree with the AP.

This explanation accounts for why you’d capitalize Delta, but what about “variant?”

In other proper nouns in classes, you capitalize the whole word, including the class: “Atlantic Ocean,” “Electric Avenue,” “Stanford University,” “the Harlem Shuffle.”

To my eye, this is why “Delta variant” seems wrong.

This is a subjective opinion. I’d welcome comment from copy editors as to why this is incorrect, but until then, it’s “Delta Variant” for me.

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  1. Technologists, MBAs, marketers, demagogues and Germans capitalize too many nouns. Only Germans have an excuse. Because “delta” is neither a geographic location nor a person’s name, it’s not necessarily a proper noun. Its adjectival use is generic and can be left in lower case. As a highly infectious strain of a deadly virus, the delta variant is already noteworthy. It doesn’t need typographic inflation to Seem More Important.

  2. I’m not sure your explanation of lower-case diseases is correct. I think it is because they are common/generic, rather than a grouping (some are, some are not).

    It is interesting that the current disease naming conventions do not allow such names as Zika, Lou Gehrig’s, Legionnaire’s, Alzheimer’s, West Nile, Spanish flu, etc.

    BTW, delta/Delta ought to be italicized as it is Greek.


    There are articles galore on naming; a COVID-specific one is in the 09JUN21 edition of Nature Microbiology.

    PS: I attended a thought-provoking talk on COVID tracking in poop yesterday in Vegas.

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