By Daniel Peixoto Irby
UCB-UCSF Joint Medical Program, MS Candidate 2013, MD Candidate 2015

A Doctor's Tricks

How doctors remember things is important-- but sometimes medical habits betray a troubling prudishness about sexual matters. Let’s talk about herpes, for example. As a medical student, I make friends with mnemonics (memory devices, such as GET SMASHED for the causes of pancreatitis, which includes “scorpion sting” for the curious). We have oodles of these things, from the memorable “S2, S3, S4 keep the penis off the floor”), to the ho-hum, “Tzanck heavens I don’t have herpes”-- but wait, the helpful reminder about the diagnostic utility of the Tzanck smear aside, what is up with that? Medical students don’t have herpes? I had some questions when I read that. For instance, how many people really have herpes, and what is the best way to prevent its spread (a natural question when you don’t just assume that people with herpes are shadowy, distant “others”)? Well, the fact is that herpes has been dubbed “The Hidden Epidemic.”

Herpes by the Numbers

First some quick background: HSVs (short for “herpes simplex viruses”) 1 and 2 cause oral and genital herpes (oral herpes is often called cold sores). HSV 1 is traditionally more likely to cause oral herpes while HSV 2 is traditionally more likely to cause genital herpes. However, each viral type can cause the other type of infection, and there is some evidence that HSV-1 is overtaking HSV-2 as the leading cause of genital infection. By the numbers, HSV-2 accounted for over 775,000 new infections in 2008, according to the CDC, making it the #5 STI in terms of new infections. But when new and total infections are added up, HSV-2 is second only to HPV in total infections at about 24 million versus about 79 million. Herpes has no cure, so it’s understandable that infections pile up and become long-term cases. In addition, when the CDC added these figures up, it estimated only infections transmitted sexually, so the figures for HSV likely underestimate the situation. When you combine these large numbers with the fact that individuals may have infections that are symptomatic or asymptomatic, you can begin to see why something like 80% of individuals with genital herpes don’t know that they have it.

Herpes Prevention

The old school thinking on genital herpes prevention was that infectivity was highest during outbreaks of the painful fluid-filled vesicles on a red base that characterize herpes. A recent article in the well-respected medical journal JAMA found, however, that viral shedding occurred in both individuals with symptomatic and asymptomatic infections. To be sure, there was more shedding by symptomatic individuals (20% of days versus 10%), but the amount shedding was similar. It may be that unrecognized, asymptomatic shedding of herpes virus is the main driver of new herpes infections. As one doctors says, “It’s best to assume that everyone has herpes.” Tzanck heavens for science. In terms of herpes prevention, it’s important to know that the number of sexual partners increases risk, and that both condoms and antiviral therapy (sometimes called suppressive therapy) each reduce transmission, but not entirely, even if used together. For example, condoms used alone can reduce transmission by 60% or more (for sex between a man and a woman). Communication is important to these prevention techniques, clearly, but it’s also important to note that first-time episodes of genital herpes do not necessarily represent new infections, but may instead be a manifestation of recurrent infection. When it comes to thawing the ice on communication about herpes-- and knowledge about the basics of the reality of herpes epidemiology -- doctors would do well to start leading by example more often. In future posts, I will tackle other STI-related topics, and take some more shots at the pruddishness of medical culture. Tzanck you very much for listening.