How do you pronounce 1273 here? One, two, seven, three?

Efficacy and Safety of the mRNA-1273 SARS-CoV-2 Vaccine

Published: December 30, 2020

Source: New England Journal of Medicine

5 Answers 5


If you want to pronounce it the way the experts in the industry would, including the scientists and clinicians who developed, researched, and actually named it, then it's "twelve seventy-three".

From my personal experience, though I haven't been personally involved in the development of this vaccine, I work in clinical trials of experimental drugs with similar designations, and four-digit drug designations like this are almost universally pronounced, by native English speakers, as pairs of two-digit numbers (except if the first or third digit is a zero, like 0103).

There is one exception. If an expert was introducing the designation to an audience for the first time (e.g., at the beginning of a talk), he or she might spell it out as "one two seven three" the first time it was used, just for clarity. I'm quite certain that no expert would ever read the number out in full as "one thousand two hundred and seventy-three".

In this specific case, there is compelling video evidence for the "twelve seventy-three" pronunciation. You can find a video in NEJM's twitter feed where this pronunciation is used at the 0:16 mark. Even more convincingly, you can watch the FDA hearing on YouTube for the emergency use authorization of the vaccine and hear Dr. Fink (Deputy Director of the vaccines division at FDA) around 26:50, and Dr. Zaks (Chief Medical Officer at Moderna) around 1:45:29, both use the "twelve seventy-three" pronunciation.

As @JohnMontgomery mentioned in a comment, this convention isn't exclusive to designations of experimental drugs. English speakers will often pronounce four-digit years this way, like "nineteen eighty-four" and "twenty twenty-one". Other four-digit identifiers like model numbers might also be pronounced this way.

However, it would usually be wrong to pronounce four-digit amounts this way, especially if the unit (e.g., "dollars") is part of the phrase being spoken. If you have $1273 in your pocket, it's either "one thousand two hundred and seventy-three dollars" or "twelve hundred and seventy-three dollars", but not "twelve seventy-three dollars".

  • Might be worth mentioning that this convention isn't exclusive to medicine either. For instance, most native English speakers would refer to the current year as "twenty twenty-one." Commented Jan 7, 2021 at 22:16
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    I think that should read "nineteen eighty-four", not "nineteen eight four"? Commented Jan 8, 2021 at 0:41

With very new terms like this, there little established use, and a lot of variation between speakers.

As far as I can tell, this was the one-thousand-two-hundred-seventy-third mRNA substance that was tested, so reading as number "one thousand...three" is arguably "correct"

But that is "a mouthful", so most speakers will reduce it to one-two-seven-three.

I'm sure you will also hear "twelve-seventy-three". But in speech, few people will use this code at all. It is "The Moderna vaccine" The number is most useful for the scientists at Moderna (who had already tried 1272 other mRNA substances and need a name to distinguish between the trials)

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    Yeah honestly it's just a number, and unless there's an established convention for reading the number in a very specific way then it probably doesn't matter. I think the most technical way of saying it would be to read each number individually, spelling it out, but I'm sure the scientists probably say twelve seventy-three or whatever they're comfortable with in conversation Commented Jan 5, 2021 at 11:51
  • 40
    As a British English speaker my first instinct upon seeing the question was "twelve seventy three", but I could also see one-two-seven-three. I suspect one thousand, two hundred (and) seventy three would be quite a rare way of pronouncing it.
    – Muzer
    Commented Jan 5, 2021 at 18:08
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    "one two seven three" is pretty much the same amount of mouthful.
    – TylerH
    Commented Jan 5, 2021 at 20:33
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    @Muzer: American from Mid-Atlantic region, I also immediately read it in my head as twelve-seventy-three. It looks like a year, and I read it the same way, in much the same way that I'd refer to the year the Magna Carta was signed as twelve-fifteen (ay dee), and this year is twenty-twenty-one (and we mostly curse twenty-twenty, not two thousand twenty). Don't know the rules for it, just know what my brain does instinctively. Commented Jan 6, 2021 at 5:21
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    American from Midwest here. I immediately read it as one-two-seven-three. Commented Jan 6, 2021 at 16:49

Yeah, you're right. It's usually pronounced m R N A one two seven three (each letter separately), but can also be pronounced in other ways (such as one thousand, two hundred, and seventy-three as @KRyan pointed out in a comment).

A cursory search for mRNA 1273 on Youglish yielded one video where the speaker pronounces it m R N A one two seven three.

  • 4
    For reference, the ‘mRNA’ part is only correctly pronounced one letter at a time. It’s an established acronym, and that’s the only way you can guarantee you will be understood when saying it (and in fact, you should be understood by at least geneticists in almost any language if you pronounce it like that). The numbers are the only tricky part here. Commented Jan 6, 2021 at 12:09
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    Just to add, I'd say mRNA-"twelve seventy-three" instinctively. Not to say it's correct, but at least where I grew up, that's a very common usage and no one would question pronouncing a four digit number in that manner. Source: native english speaker, midwest US
    – TCooper
    Commented Jan 7, 2021 at 1:52

I would say it as 'twelve seventy three' for conciseness.

  • 8
    Welcome to ELL.SE. Answers on Stack Exchange are expected to be definitive — they should explain, rather than merely assert, and include examples, references, or links as may be appropriate. I strongly encourage you to take the site tour and review the help center for additional guidance.
    – choster
    Commented Jan 5, 2021 at 16:19
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    @choster That auto comment text might need some tweaking. For this question in particular, but even an entire site about language, it's often hard/impossible for answers to be "definitive".
    – TylerH
    Commented Jan 5, 2021 at 20:34
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    @choster well this question is a perfect example of why having that as an absolute rule is silly. There is no official or definitive answer in some cases. This answer is valuable as together with the others it shows that people have different ways of saying these sorts of things
    – eps
    Commented Jan 5, 2021 at 21:02
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    @eps There is never an official answer when it comes to English, but a good answer, again, should explain, not state. Twelve seventy-three is more characteristically American than British, for example, if you were providing a street address or phone number. If Mauricio has domain knowledge that this is convention, he should explain that. if not, he should at least describe why this is preferable to other possibilities.
    – choster
    Commented Jan 5, 2021 at 21:12
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    @choster: A phone number? Never heard anyone use it for phone numbers in American English (the song is eight-six-seven-five-three-oh-nine!). For that matter, I mostly hear twelve seventy-three for four digit numbers specifically, in many contexts (street addresses, years, etc.), but it doesn't transfer to longer numbers; I grew up at (modified for privacy) ninety-one-twenty (9120) Foo Drive, but now live at one-oh-five-two-six (10526) Bar Court. Commented Jan 6, 2021 at 5:25

Actually the proper English way to pronounce 1273 in English is to say "one thousand, two hundred and seventy-three".

The other answers are wrong as they fail to explain the proper English way of saying it, and instead they use colloquial or slang English. It doesn't matter if the scientists refer to it in the way the other answers do, as the scientists aren't using proper English either. Anyone can speak in English, but not everyone uses proper English, colloquially known as “the Queen's English”.

However, people prefer not to use the proper pronunciation as it's long and a mouthful to say, so for convenience, conciseness, and succinctness, they prefer to say "one two seven three" or "twelve seventy-three".

Saying a large number

We say large numbers by listing the numbers in order of size, biggest first. When reading a single number, all the number labels should be singular, for example 10,400 is ten thousand four hundred and not ten thousands four hundreds.

We describe three digit numbers in hundreds, then tens. Generally, in British English we usually connect large numbers with double or single digit figures with and, but in American English and is not used. Note that hundreds, thousands and millions are not connected to each other with and, though.

For example:

345 is three hundred and forty-five (three hundred forty five in American).
59,321 is fifty nine thousand, three hundred and twenty one. (not fifty nine thousand and three hundred…)

Naming large numbers exercise

Practise reading these numbers out loud:

Suggested Answers

4,567 – four thousand, five hundred and sixty-seven

Source: https://englishlessonsbrighton.co.uk/saying-large-numbers-english/

  • 1
    This has been downvoted by others without explanation, so I'll speculate as to why: 1) People learning English would probably find the conversational pronunciation helpful, even if it's not "proper." Dismissing a common pronunciation as wrong does a disservice to askers and insults answerers. 2) Context matters. If I pronounced a numeric quantity, like $1,273, as "twelve-seventy-three dollars," many people would be confused. But the context here ("mRNA-1273") is a name and arguably has no "proper" pronunciation. You wouldn't pronounce a zip code or phone number this way, either. Commented Jan 7, 2021 at 20:20
  • Saying an answer is wrong is not an insult. It is not an attack on someone's intelligence or skills.
    – desbest
    Commented Jan 7, 2021 at 20:34
  • I don't think this answers the question. The question was how to pronounce mRNA-1273, not how to pronounce 1273 in isolation; and the answer is not necessarily the same. Context is important. Also, your assertion that there's such a thing as "proper English" is highly debatable. Commented Jan 10, 2021 at 17:49

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