In August 2013, Cat and co-National HELP administrator Auburn G. Locks met with two of the herpes community’s top researchers, Terri Warren of Portland’s Westover Height’s Clinic and Dr. Anna Wald of the Virology Research Center at the University of Washington. The goal was to clear up some confusion, and solidify some elements, in our ongoing investigation of the behavior of the herpes simplex virus (HSV), the virus that causes our herpes outbreaks. The hope is to continue to improve our understanding of HSV and learn to apply it to living with and managing the virus in our lives.
We are profoundly grateful for the generosity of time and knowledge that these two eminent medical professionals of our H community shared with us.
What follows is a report on those conversations.
How many people in the United States have HSV?
There are no exact percentages available for this statistic. However Dr. Wald’s best estimate is that “about 75%” of all Americans have one or both types of the herpes simplex virus.
She also shared that people with HSV-1 (either genitally or orally) make up “about 65%” of all Americans.
How many people in the U.S. have genital herpes?
The answer is more complicated than what our official statistics can provide. To begin with, it’s important to remember that genital herpes can be caused by either HSV-1 or HSV-2.
The officially reported figure of Americans with HSV-2 (oral or genital) is 16.2%, or 1 in 6. However, this figure is calculated from a well-regarded ongoing survey by the National Health and Nutrition Examination Survey (NHANES)  using blood samples collected only from people 18-49 years of age. According to the US Census Bureau , this figure would seem to represent over 20 million people in this age range who have HSV-2.
A 2008 CDC report on STI prevalence , however, placed the total of new and existing oral and genital HSV-2 carriers at about 24.1 million Americans. The primary data for this figure comes directly out of the NHANES survey, raw data that totals 19% of Americans 18-49 years old, almost 3 percentage points higher than the official percentage reported by various credentialed sources. Dr. Wald explained that the raw figure from NHANES, 19%, has been adjusted to correctly reflect U.S. demographic data, resulting in a figure of 16.2%. This could explain the discrepancy.
The idea that the percentage of HSV-positive people goes up as we get older has been a long-held assumption in the H community, but Dr. Wald expressed some skepticism that this is the case. She introduced the impact of the Cohort Effect, the idea that the contribution to the overall statistic of HSV carriers differs among generations. We perhaps should consider, for example, that people who are now in their 80’s were in their 20’s in the 1950’s, when sex before marriage was quite taboo, and also that acceleration in genital HSV transmission did not begin until the mid 70’s to early 80’s.
So to answer the original question of how many Americans have genital HSV, we have to take a number of different statistics into consideration. 16.2% of people aged 18-49 have HSV-2. Some of them have oral HSV, not genital HSV. Furthermore, according to a number of official studies , at least 1/3 of genital HSV cases stem from Type 1 rather than Type 2. If we were to do the somewhat complicated math, based on the variety of official findings, we would probably find that 1 in 5-6 Americans, or somewhere between 16-20%, aged 18-49, have genital HSV of either Type 1 or Type 2 (or both). There does not appear to be any current data for populations 50 years of age and older, or younger than 18 years.
The statistics don’t matter in the end, but these pretty good ballpark figures could be useful those among us who are curious about numbers.
How reliable are the available tests for HSV?
The Focus ELISA
The possibly earth-shaking news is that the blood test that’s commonly used by the medical community to detect HSV, the HerpeSelect ELISA by Focus Diagnostics, now owned by Quest Laboratories, has been found by investigative studies to have a high degree of inaccuracy. It generates a percentage of false results. Though some other IgG tests appear to have similar problems, the ELISA has been the most investigated.
In particular, Dr. Wald cited low sensitivity to HSV-1 (sometimes the test misses HSV-1 completely) and faulty specificity (sometimes the test thinks HSV-2 is HSV-1) as particular problems with the Focus ELISA. Terri also spoke about the prevalence of false positives from this test. She cited a percentage of 5.5% who test in the low positive range with the ELISA. About half of these turn out to be false positives, which according to Terri means “that 2.25% of people who are tested nationally are being told they have herpes when they don’t.”
Terri discusses IgG testing reliability:
The Western Blot
Terri claimed that the Western Blot, the gold standard of HSV testing, was “not perfect either,” but when asked about its degree of accuracy, she called it better than 99%. She revealed that while some of the IgG tests like the HerpeSelect ELISA will sometimes display a seroreversion, in which a formerly positive patient suddenly tests negative, this is not characteristic of the Western Blot.
Both Terri and Dr. Wald echo the recommendation for using the Western Blot as the confirmatory test for inconclusive results from IgG, especially those in the low-positive range. Dr. Wald’s view is that multiple office visits and tests with the IgG would probably cost the patient just as much as choosing the Western Blot right away. Unfortunately, because the labs no longer offer it, there are now only two ways to order the Western Blot: directly from the University of Washington or via a consultation with Terri at her clinic, since it appears she is now the only clinician who can still order the test from Quest Labs.
Antivirals and Blood Tests
Terri shared an important discovery regarding the impact of antiviral medication on blood testing for HSV. It appears that taking the antiviral medication at the onset of the primary infection can delay the production of antibody, which extends the length of time before the test can return a positive result.
Terri discusses antivirals and testing:
With regard to swab tests, both Dr. Wald and Terri expressed the view that culture tests should really no longer be used for testing, and should be replaced by the far more sensitive polymerase chain reaction (PCR) tests which amplifies the virus’ DNA to detectable levels. These have the highest level of accuracy, though Terri did cite rare false results with the PCR, citing lab error and cross-contamination as a possible cause. She also brought up cases of inaccurate HSV typing, but said these did not happen often.
Terri discusses PCR versus culture tests:
Did my HSV move from one place to another?
To preface this discussion, the virus can cause an outbreak anywhere within its dermatome—the area of skin innervated or fed, by the ganglion or ganglia or nerve bundle(s), that the virus lives in. In the case of genital HSV, for example, which lives in the sacral ganglia, Terri Warren tells us that the virus can cause an outbreak on the buttocks area, “and on the back of the leg also and into the foot…we’ve had people with recurrences on their feet.”
Dr. Wald discussed the innervation of the upper torso and arms by the trigeminal ganglia, the same nerve bundles that oral HSV lives in. Herpes Whitlow and Herpes Gladiatorum are caused by the same virus that causes our oral herpes.
Dr. Wald also informed us that the various available dermatome maps differ from one another, so it’s not always easy to pinpoint the boundaries of each dermatome. In addition, both Dr. Wald and Terri talked about their being overlap among certain dermatomes, specifically discussing the lumbar and sacral regions.
The most interesting piece of this discussion concerned herpes infections of the eyes, ears, and nose, which both Dr. Wald and Terri believe are most likely to be recurrences of oral herpes, rather than re-infection from an external source. Terri discussed the likelihood that ocular herpes, herpes of the eye, is caused by the virus traveling from its nerve bundle at the base of the neck, up the trigeminal nerve to the eye.
Terri talks about dermatomes and moving outbreak locations:
Can I transmit my HSV type to my partner who has a different HSV type?
Dr. Wald does not agree with the long-held “official” statistic that HSV-1 antibodies always provide 40% protection against contracting HSV-2. That figure comes from an older study. There have been several studies since that contradict that figure. At one of Auburn’s support meetings within the last couple of years, Terri Warren expressed her belief that HSV-1 antibodies do not have any confirmed effect on HSV-2 transmission.
However, Dr. Wald reiterated her quote that it is all but impossible to transmit HSV-1 to someone who already has HSV-2 antibodies. She referred to two “confirmed” documented cases of this happening in her 30+ years of HSV research, cases that appear to be recent. However, Terri Warren posited that there is no true confirmation of these cases, partly because of the very problematic HSV blood tests that are in wide use at the moment, and that have shown inconsistent accuracy levels. Terri herself has never seen a case of someone with HSV-2 contracting HSV-1 after “immunity.”
Terri discusses HSV antibody types and transmission:
Can I be re-infected with the same HSV type that I already have?
Our understanding for many years has been that after 12-16 weeks, the body generates enough antibodies throughout the system to prevent becoming re-infected with the same viral type. Our conversations with both researchers appear to confirm this idea, with some further details on the subject.
As explained by both researchers, 16 weeks is the amount of time by which most new HSV patients will make antibody, which Terri defines as the body having “mounted a good immune response.” Terri reiterated that it would therefore be smart to wait 16 weeks to get an accurate result. This is borne out by Western Blot reports over the years. Both she and Dr. Wald have found autoinoculation—passing the virus from one part of the body to another—to be”rare” or “unusual” after the body has mounted an immune response, which according to Terri’s definition, would be no later than 16 weeks in most cases.
Dr. Wald believes that this “immunity” actually happens much sooner, perhaps even before the antibodies are detectable by blood testing. Both Terri and Dr. Wald used the example of children who get HSV: if it were easy to autoinoculate, children, whose immune systems are not as developed as adults’, would have cold sores all over their bodies.
This would seem to answer the question of re-infection with the same viral type from other external sources such as a sexual partner, something that, according to Dr. Wald, rarely if ever happens, especially after “immunity.” She does posit that if it ever were to happen, it would likely not change the frequency or pattern of recurrences. Furthermore, Dr. Wald agrees that if HSV-2 antibodies can provide a shield against contracting HSV-1, it makes sense that it would also block other strains of its own type.
Terri discusses immunity, autoinoculation and reinfection:
Are there people with HSV who don’t shed, and are therefore not contagious?
First, it’s important to remind everyone about the phenomenon known as asymptomatic shedding—we can shed virus even without symptoms, and therefore could be contagious at any time without knowing it.
Dr. Wald shared something that knocked our socks off: because studies on HSV transmission rates require discordant couples, in which only one partner has HSV, they had to find couples willing to participate in the study together who also tested via swab as discordant. Naturally, such couples were likely to have been together for some time—it’s not likely that a couple who just met in a bar would join a study on transmission risk. Chances are couples would be somewhat committed to one another to take the risk of possible transmission.
In fact, the median length of time that the discordant couples accepted into Dr. Wald’s studies have been together is 18 months. What’s significant about this is that clearly there exists committed sexual partnerships out there in which transmission has not occurred even after 18 months together. This would seem to corroborate the theory that some HSV-positive people are naturally low-shedders.
Of course, there is no any data about what kinds of precautions these pairs had been taking prior to entering the study—some or most could have been on medication and using condoms, which could explain their having avoided transmission for 18 months. However, we do have some anecdotal evidence of HSV-positive people who use neither protection nor medication in their sexual lives, and whose partners consistently test negative for HSV.
It’s important to remember, however, that the only way to determine that transmission has not occurred, is for the non-infected partner to test negative for the virus at least 4 months following the last sexual contact with the HSV-positive partner.
1. National Health and Nutrition Examination Survey, 2011-12. The 16.2% figure represents an adjustment of the raw data to more accurately reflect actual likely demographic distribution. Dr. Wald revealed that the study oversamples minority populations.
3. US. Census Bureau. This data represents population figures in 2012, the year of the last NHANES Survey report.
2. Centers for Disease Control. Incidence, Prevalence, and Cost of Sexually Transmitted Infections in the United States. February 2013. HSV data is from 2008 studies. From a comparison of the NHANES surveys since 1976, it appears the NHANES surveys, the incidence of both HSV-1 and HSV-2 has been steadily declining.
4. Wald, A. “Genital HSV-1 Infections.” Sexually Transmitted Infections. June 2006.
5. Cherpes, Thomas A., et al. “Longitudinal Reliability of Focus Glycoprotein G-Based Type-Specific Enzyme Immunoassays for Detection of Herpes Simplex Virus Types 1 and 2 in Women.” Journal of Clinical Microbiology. February 2003.
6. Mark, Hayley D., et al. “Performance of Focus ELISA Tests for HSV-1 and HSV-2 Antibodies Among University Students With No History of Genital Herpes.” Sexually Transmitted Infections. September 2007.
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