vaccines Archives - of Sex and Love

Science of Sex: The Complexities of Herpes

December 21st, 2019

Herpes

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

Comment

Categories: Science of Sex

Science of Sex: HPV and the HPV Vaccines

June 17th, 2017

Welcome to the fourth installment in a new feature on Of Sex and Love: Science of Sex. In this feature, I plan to discuss the science of sexuality in an easy-to-digest format that’s accessible to the casual reader. I will also follow up with some extended reading material for people who want to know more about the subject of each post.

Enjoy!

Science of Sex HPV

Human Papilloma Virus in a Nutshell

HPV is the virus that causes genital warts, but just because you don’t have any symptoms doesn’t mean you don’t have HPV. It’s one of the most common sexually-transmitted infections with over 200 strains (strains 16 and 18 cause over two-thirds of all cervical cancer while low-risk strains 6 and 11 cause most warts). Over 80 million people or about 1 in 4 people have it. It’s easy to transmit through skin-to-skin contact, so even using condoms may not prevent HPV. The CDC advises that ‘nearly all’ men and women will contract HPV in your life, and it’s likely that many people don’t even know they have it.

HPV doesn’t just cause warts. It can lead to irregular PAP smear results for women and cause cervical cancer (HPV can also be the culprit for other cancers, including that of the throat and anus). Those results can lead to a woman getting tested for HPV, but there is currently no test for HPV in men who have an asymptomatic strain (some sources indicate that a test does exist but it’s expensive and invasive).

Treatment of HPV may mean doing nothing at all. Most cases clear up within two years, but this isn’t always the case.

The HPV Vaccine

A vaccine for several of the most common strains of HPV, including some that cause cervical cancer, Gardasil, became available about 10 years ago. There are now three different vaccines for HPV available (Cervarix, quadrivalent Gardasil, and 9-valent Gardasil-9), the latter of which cover more strains of HPV than the original. One study concludes that HPV vaccines can prevent “most” invasive cervical cancers (around 70% of cervical cancer for the 9-valent vaccine and 66% for original Gardasil) as well as some oral cavity, penile, laryngeal and vulvar cancers. These vaccines are at least 90% effective at blocking those strains.

The vaccines consist of two or three doses, which can depend on schedule or your age. Even if you can’t take all shots within this time frame, you’ll still benefit from at least one dose. Similarly, the vaccine is still beneficial if you’ve already become sexually active, but it’s more beneficial if administered before sexual activity. In this case, the younger the better.

Note: While the HPV vaccine was previously approved for young adults up to 27 years, the CDC has approved it for use in adults up to 45 years old.

Although at first recommended for girls, HPV vaccines are beneficial for boys who can contract and transmit HPV. But it’s less likely that a male will no if he’s HPV-positive, which means he’s more likely to transmit it to a partner.

Still, fewer boys than girls are being vaccinated (12% of boys had received all three doses compared to 36% of girls in 2013), and vaccination occurs at a later age. Fortunately, vaccination rates have increased through the years, perhaps as no serious side effects have arisen over the years and the efficacy of the vaccines have been proven. For girls, infections by strains of HPV that the vaccine prevents has dropped 64% since 2006.

Let’s hope that vaccination rates rise, gaps close and strides can be made to cover more strains of HPV in future vaccines!

Further Reading