The last Science of Sex is about herpes and, more specifically the two viruses and why it’s been so difficult for us to find a vaccine for an STI that’s become increasingly common, perhaps because people do not realize that it can be spread even when there’s no outbreak. Herpes is spread through skin contact, which makes it easy to pass or contract, similar to HPV. And while there are medications to prevent and suppress breakouts, which come in the form of sores, a vaccine would go a long way to prevent that need in the first place.

Most people know about herpes but may not fully understand it. First, there are two viruses: Herpes Simplex Virus 1 and Herpes Simplex Virus 2. 6 million years ago, both viruses diverged from an ancestor.

While you may you may have been taught that HSV1 is “oral” herpes, that oversimplifies the subject. While HSV1 causes most cases of oral herpes, which 1 in 2 people have in the United States, those that give you cold sores, it can be transmitted to genitals through oral sex.

It’s possible for one person to have both viruses.

Furthermore, the two viruses like to mingle. It’s not uncommon for these viruses to mix, or recombine, and they’ve been doing this for some time. Most viruses of “genital” herpes contain DNA from oral herpes.

However, it’s possible for the two viruses to mix in new and unusual ways. A more recent study found a strain of HSV1 that contained ten times as much HSV2 DNA. The chunk was ten times larger than typically occurs. This particular mixture belonged to one patient who had genital infections of both HSV1 and HSV2 (known as co-infection) and the DNA mixed in that person specifically.

Interestingly, it always appears that genital herpes picks up chunks of data from oral herpes and not the other way around.

Aside from interesting, this could potentially be frustrating to researchers who want to create a vaccine for herpes. If they target HSV2 but the strain contains large chunks of HSV1 data or is able to swap out that DNA, the vaccine may not be effective.

Currently, we only have three antiviral medications available to treat existing herpes infections and no vaccine to prevent new infections. These medications enable people with herpes to live normal lives. However, there are times when herpes has led to recurrent keratitis, which can cause blindness, encephalitis, and other diseases, especially in people with compromised immune systems.

We may be closer to a vaccine than not, however. The company Excell Biotech is currently testing a herpes vaccine on animals with hopes to go into clinical trials next year. Another company, X-Vax, is looking into creating a herpes vaccine by altering the virus in an attempt to prompt the body to create a different type of antibody.

While one or both of these vaccines might prove dependable and come to market, it’s really too soon to tell. At least two previous attempts to make a herpes vaccine have failed. Last year, Genocea Biosciences abandoned their attempt at a herpes vaccine after a positive Phase II before heading to the next phase. Also in 2018, Vical gave up its attempt at a herpes vaccine after a failed trial.

Prior to that, a company attempting to create a vaccine against HSV2 actually found that the vaccine only protected against HSV1 in some cases. The way the two viruses mix could potentially explain that strange failure.

But that doesn’t mean we shouldn’t try, especially when teens might be at greater risk of contracting herpes than prior generations.

Further Reading

• Herpes Vaccine: Despite Setbacks, There is Still Hope
• More bad news for Vical as it abandons herpes vaccine program
• Abandoned Genital Herpes Vaccine GEN-003 Found to Reduce Lesions, Decrease Viral Shedding at Varying Doses
• Jupiter biotech scores $56M to defeat herpes, in a field littered with failure
• Failed herpes vaccine puzzles virologists
• Today’s Teens More Prone to Genital Herpes, Study Suggests
• The Oral and Genital Herpes Viruses Are Having ‘Sex.’ The Result Is Worrisome.
• Large, Stable, Contemporary Interspecies Recombination Events in Circulating Human Herpes Simplex Viruses

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