Can the CDC Be Wrong?

On July 18, 2014, in Blog, Education, by Admin

Can the CDC Be Wrong?

Every now and then, we get people coming through and claiming our statistics must be wrong, because they read/heard/saw somewhere, some conflicting information. It never seems to cross their mind that, perhaps, we just work a bit harder than everyone else. It happened just recently when we mentioned that “around 75% of the US population carries HSV”.

Not everyone studies HSV or HPV full time. You’ve got your herpesvirus research labs, your virology research clinics and… well… us.  While agencies such as the NIH, CDC, NIAID, etc certainly perform a lot of research and compile a lot of data, they don’t focus solely upon HSV & HPV.   They also have to play by a different set of rules when it comes to development of their statistics, as they’re in charge of taking care of the healthcare of the US as a whole. Their statistical compilations focus upon national numbers derived from research initiatives such as the National Health and Nutrition Examination Survey (NHANES); the US national health census.  Huge project. It’s an enormous undertaking and the numbers that come out of it, no doubt, are some of the best available for getting national numbers; the big picture.

However, it’s quite expensive and time-consuming so the NHANES certainly isn’t feeding us new HSV & HPV numbers annually, nor are they doing anything but blood tests to determine type; they must make assumptions about actual infection location. Sometimes it’s a few years in between. To fill in some of those time gaps, they may also apply mathematical and computer projection modeling which, again, produce solid information. The CDC does a damn fine job.

We ourselves rely upon the CDC as one of our primary sources, since they are sure to have accurately modeled and assessed national numbers.  However, we also understand the limitations of what they’re actually testing.  For more specific topics, we may rely upon our own advisors to analyze the body of research, compare and contrast the information we get from each and come to a consensus. All together, they tend to give a more accurate depiction of what is true and where more research and documentation is required.

No entity is infallible, though (including our own). We do notice minor things here and there – not necessarily in the research itself, but in the manner in which it is being communicated which could be improved upon.  Things which the CDC might not notice, but can be quite detrimental to ensuring that the public ends up getting the best information or fully understanding the information they’re given.

A few of those errors have been on the CDC website itself. You see, for some time, there was a belief among the general public (and even in public health) that Genital Herpes was always HSV-2. That model worked fine for decades and even the CDC ran with that paradigm for many years. In fact, the website, in 2012, actually stated both of the following:

  • 16.2% of people ages 14-49 in the US carry HSV-2
  • 16.2% of people ages 14-49 in the US have Genital Herpes

To the untrained reader’s eye, there doesn’t really seem to be anything wrong with that. However, at we “research the research” on a daily basis. While they may seem the same at first glance, they are not. The difference sticks out like a sore thumb in our eyes.

Why? Because after reviewing thousands of research studies and compiling countless statistics ourselves, we knew that it is impossible for both of those statements to be true in the current HSV climate; one of them was most definitely false.

Can you guess which one?

The answer is B. HSV-1 infects genitals, too, so we can be absolutely certain that there are more people with Genital Herpes than merely those with HSV-2. The Genital Herpes number, if accurate, must be higher.

Digging into the research indicates that HSV-1 is responsible for quite a bit more. Depending upon the population group, we’ve seen studies indicating that the percentage of Genital Herpes infections which were actually HSV-1 (rather than HSV-2) has shown to range from the mid-30th percentile up to the 90th percentile, depending upon the population group. Further, they began to prove this way back in the 1970’s.

So why isn’t the CDC reporting this?

Well they are now to a degree. We can’t be certain it had anything to do with us, but we did let them know that they really should not be using the latter statement – that since a considerable percentage of Genital Herpes infections are in fact known to be HSV-1, the Genital Herpes statistic cannot truly be the same as the HSV-2 statistic; it’s mathematically impossible.

And, since then, the language on the CDC site has begun to be adjusted. They even mention now that:

Genital herpes infection is common in the United States. Nationwide, 16% of persons aged 14 to 49 years have HSV-2 infection. The overall prevalence of genital herpes is likely higher than 16.2%, because an increasing number of genital herpes infections are caused by HSV-1. Increases in genital HSV-1 infections have been found in patient populations worldwide.

Much more accurate.

Now we run into another issue, of sorts. You see, the CDC had been using NHANES-derived information in order to develop their Genital Herpes statistics. However, the NHANES doesn’t actually quantify Genital Herpes. The only thing their blood tests ever actually ever measured was HSV-2 antibodies: seroprevalence.  And, since a blood test cannot tell you where an infection actually is, whatever numbers you do come up with will not be truly correct for Genital Herpes; only for HSV-2 infections, somewhere on the body. An untold number of HSV-2 infections are not genital and the NHANES isn’t making any differentiation between locations. So technically, the CDC numbers don’t measure Genital Herpes at all. They measure the prevalence of a virus which is known to usually infect genitally in humans.  That’s not to say the information is junk. It does tell us how many people carry HSV-2 and that is certainly valuable information to track.  It’s just questionable if they imply – or allow the reader to infer – that all those are genital infections, or that the number in any way represents all genital herpes infections.

In their defense

Being a scientific body, the CDC certainly does use their citations and, in the fine print, it is certainly and appropriately clarified that these numbers are based upon the seroprevalence of HSV-2 antibodies.

 New problem: the public never reads the fine print.

All the lay reader sees is that 16.2% of the people in the US have HSV-2. They grab that and run off and tell the world that 1 in 6 have Genital Herpes and they’re sure of it because the CDC said so. Well, the CDC offered a lot more qualifying info for that statistic, too, but the people didn’t get (or transport) that message. That isn’t the CDC’s fault, though. That’s the reader’s fault.

There’s another very common misconception that merits a discussion. The CDC website hardly even broaches the subject of oral herpes… and HSV-1 is far more prevalent in our society – in any society – than HSV-2.  And again, people tend to overlook that and just use the CDC’s HSV-2 seroprevalence statistic and claim that’s how many people in the US “have HSV”.  Now they are really off the mark.

In 2004, the most recent research for the time indicted that 57.7% of the population, ages 14-49 carried HSV-1. This, too, was measured via blood test in the NHANES, but scarcely gets a mention on the CDC website itself, as “People aren’t concerned with HSV-1. That’s not an STD; that’s a cold sore.” That’s what the story used to be, anyway, but science has known for decades that it wasn’t actually the truth. Because of the body of research, we know without question that HSV-1 can be equally, if not more responsible for the number of Genital Herpes infections today and likely is responsible for more. Any HSV-1 or HSV-2 infection could feasibly end up on someone’s genitals, through vaginal, oral, anal or manual sex or some other form of direct contact with the infected area. Mainly genital or oral infections, but a herpes infections of the fingers – Herpes Whitlow – is the #3 location for a herpes infection, so don’t rule it out too readily.

The final point we must discuss is what the previous few paragraphs actually mean for us: while an untold number of people have Genital herpes infections, anyone with HSV of either type could possibly give someone a genital herpes infection…. and isn’t that really the part we all ought to be focusing upon when discussing risk of transmission?

That’s what a partner or any other audience really needs to know.  Not how many have a single type, or in a single location, but how many people can give them HSV anywhere, including their genitals.  Most assuredly, that is their chief concern.

So, when you put together the total HSV-1 and HSV-2 seroprevalence, you are just shy of the 70%, assuming there is some portion who carry both types… and there certainly are some.

Wait. Didn’t we say 75% earlier? What just happened?

Research happened.

We have new, updated numbers!

As of the latest compilation, published in a paper by CDC researchers:

“In 2005–2010, the seroprevalence of HSV-1 was 53.9%, and the seroprevalence of HSV-2 was 15.7%.  From 1999–2004 to 2005–2010, HSV-1 seroprevalence declined by nearly 7% (P < .01), but HSV-2 seroprevalence did not change significantly.”

No, these aren’t reflected anywhere yet and the changes won’t be made on our site, either, until we have conferred with both our internal research partners and the CDC in order to gauge the confidence with which we can begin to publish them.

One last example, just so we can show you this really has little to do with the CDC and a lot to do with keeping up to date on the latest information from every source.


There are now nine human herpesviruses:

  1. HHV1
  2. HHV1
  3. HHV3
  4. HHV4
  5. HHV5
  6. HHV6a
  7. HHV6b
  8. HHV7
  9. HHV8

Now, go see if you can find any other source out there which will tell you that there are more than eight human herpesviruses.

  • The taxonomy of HHV6 was reclassified to HHV6a & HHV6b in 2011 by the International Committee on Taxonomy of Viruses.
  • It was ratified in 2012
  • made the adjustment immediately upon ratification, because we know the ICTV is actually in charge of worldwide viral taxonomy; they are the ultimate source for the subject. They’re the ones who actually name them.

That news didn’t reach the US National Library of Medicine unit May of 2014.  2 years later.  Not because the information wasn’t available, but because is actually out there hunting for the most accurate, up-to-date information, whereas most others, by nature of their business, simply waiting for information to filter down to them.  And there’s nothing inherently wrong with that, but it does give reason for why some information on might not match what others are stating.

So when you see our numbers not-quite-matching some other source – any source – it may well be because we’re ahead of the curve. We strive very hard to ensure that we always provide you with the most accurate, up-to-date information available anywhere.

So can the CDC be wrong?  Of course they can; any of us can be wrong, in regard to either our calculations, our communications, or our personal interpretations… a misunderstanding by readers themselves.  However, by working together, we can ensure that everyone remains current including you, our readers.  If you don’t understand something – if something doesn’t seem to make sense – don’t be afraid to ask!  We’d be happy to clear up any confusion.  That’s what we’re here for.

[ed. note: The CDC website still says.. “about one out of every six people aged 14 to 49 years have genital herpes.”   We’ll be sure to remind them that in order to be as accurate s possible, it should actually read “HSV-2”, rather than “Genital Herpes” and that research indicates that the prevalence of “Genital Herpes” is quite likely twice that number.]


Dedicated to our wonderful friends at the CDC, who somehow manage to tolerate us.

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