STD Awareness: Winning One War on Cancer

Cancer starts with the uncontrolled division of cells.

The developed world is in the midst of a huge nosedive in genital warts and cervical “precancer” — all thanks to the human papillomavirus (HPV) vaccine. This simple shot trains the immune system to defend itself against HPV, a virus that causes genital warts and several types of cancer. Most sexually active people will be exposed to it in their lifetimes — it’s even been nicknamed the “common cold” of sexually transmitted infections.

Gardasil 9 protects against seven strains of HPV that collectively cause 90% of cervical cancers and anal cancers, plus the two HPV strains that are jointly responsible for 90% of genital warts. Vaccination also reduces the frequency of “precancers,” which are cellular abnormalities that can be treated before progressing into full-fledged cancer — meaning less time, money, and anxiety spent dealing with follow-up procedures and treatments.


The HPV vaccine is an anti-cancer vaccine.


The vaccine is safe and effective — and when we say “effective,” we mean it could lead to the eradication of HPV, and with it the cancers it causes. A recent analysis of 66 million vaccine recipients published in The Lancet points to plummeting rates of genital warts and precancer. Among teenage girls, there was an 83% drop in HPV-16 and HPV-18 infections (the two strains of HPV that together cause 70% of cervical cancers) — and cervical precancers were cut in half.

The most dramatic gains were made in countries that offered the HPV vaccine to both boys and girls. Additionally, there were even decreases in the HPV strains that aren’t covered by the vaccine — evidence of “cross-protection,” the phenomenon in which the immune system recognizes close relatives of the viruses it has been trained to attack. Even people who did not receive the vaccine were less likely to catch the virus, simply because their risk was reduced if their partners were vaccinated. Continue reading

STD Awareness: Can I Get Gonorrhea from Kissing?

Not all types of kissing feature the exchange of saliva.

Some pretty depressing news hit a couple of months ago, when headlines proclaimed kissing could allow gonorrhea to jump from one person to another.

We already knew gonorrhea could be transmitted during oral sex — a terrible fact, given that most people don’t use condoms or dental dams during oral sex. And we knew that oral gonorrhea is more likely to develop drug resistance, which could be helping to drive the possibly untreatable gonorrhea of the near future.


Mouth-to-mouth kissing could be transmitting gonorrhea right under our noses — literally.


Gonorrhea is most famous as an infection of the cervix or the urethra. But the bacteria that cause gonorrhea can thrive in other warm, moist areas of your body — not just the reproductive tract, but also in the mouth, throat, eyes, and anus. Unprotected oral sex can allow those bacteria to travel in either direction between one person’s genitals and another person’s throat.

But what about mouth-to-mouth kissing, like French kissing? Is that enough to allow these bacteria to hitch a ride from one mouth to another? Previous research, using a mathematical model, estimated that mouth-to-mouth contact might be a significant — and underappreciated — mode of gonorrhea transmission. But that was a mathematical model, a sophisticated equation using what we know about a population’s gonorrhea prevalence and sexual behavior to estimate how frequently the infection is transmitted from one mouth to another. Continue reading

STD Awareness: How Common Is Herpes?

Those of you with an eye for weird news might have noticed recent headlines about wild monkeys in Florida suffering from a herpes epidemic.

Two things in that sentence might have tripped you up. One, Florida has wild monkeys? Yup. In the late 1930s, after a Tarzan movie was wrapped, three male and three female rhesus monkeys were released into the Florida wilds, giving rise to an estimated 1,000 monkeys roaming the Sunshine State today.


Both oral herpes and genital herpes are on the decline.


The second thing that might have given you pause: Monkeys can get herpes? Yes again! The Herpesviridae family is huge, with at least 100 members infecting mammals, birds, reptiles, bony fish, amphibians, and oysters — even dinosaurs are thought to have been infected by herpesviruses! The virus has been evolving alongside us since before the dawn of humanity, so it knows us like the back of its hand (metaphorically speaking), allowing it to stow away in our bodies and hide from the immune system.

The “Tarzan” monkeys suffer from a type of herpesvirus called herpes B, which can be deadly in humans, though it’s rare — just try not to find yourself on the receiving end of a monkey bite or scratch. Not so rare in humans are human herpesviruses, of which there are eight types. Types 1 and 2 — aka herpes simplex virus (HSV) 1 and 2 — can both cause genital herpes, one of the most common sexually transmitted diseases (STDs). HSV-1 mostly causes cold sores, but can also infect the genitals to cause genital herpes, while HSV-2 mostly causes genital herpes, but can also infect the facial area to cause cold sores. (A little confusing, I know.) Continue reading

STD Awareness: The Long Road to a Chlamydia Vaccine

Earlier this year, television personality John Oliver was the butt of an elaborate prank orchestrated by actor Russell Crowe. It started with an auctioned jock strap, and ended with Crowe funding the John Oliver Koala Chlamydia Ward at the Australia Zoo. If you want the full story, check out the video below (beware explicit language).

Despite Oliver playing it for laughs, koala chlamydia is very real and very serious. At least half of wild koalas are infected with a chlamydia type that’s related to the human version. As in humans, koalas can transmit these bacteria through sexual contact. And, similar to the havoc it wreaks in our species, in koalas chlamydia can cause blindness, urinary tract infections, and female infertility — and can be passed from mother to infant. Along with other factors, chlamydia is said to be responsible for plummeting koala populations in many parts of Australia. Continue reading

STD Awareness: The Good, the Bad, and the Ugly

Sexually transmitted diseases (STDs) have been with us since the dawn of time — or at least since the dawn of sex. And, as we continue to hone our approach to preventing and treating them, STDs will always grab headlines, whether the news is bad or good.

The Good

Can the HIV epidemic be stopped?

For more than a decade, AIDS, the illness caused by HIV, was seen as a death sentence. It wasn’t until the mid-’90s that antiretroviral drugs kept the virus in check, prolonging lifespans for people with access to these medications and transforming the infection into a chronic disease. Now, those dreaming of an end to HIV are seeing reasons for optimism. No, a cure isn’t in the works — but many researchers believe we can end the epidemic through prevention.

Ending HIV transmission will take money and an efficient health care infrastructure, but we have the tools to do it. It starts with expanding access to HIV testing — an estimated 15 percent of Americans with HIV are unaware of their status. The next step is to ensure that everyone testing positive has access to antiretroviral drugs. When used correctly, these medications keep viral levels so low that the chances of transmission are virtually nonexistent. More recently, medications called PrEP — pre-exposure prophylaxis — enable people without HIV to protect themselves from infection. Condoms, of course, are a time-tested prevention tool. Gathered together, we have a pretty mighty arsenal. Here in the United States, we could stop HIV transmission in its tracks in just a handful of years. Of course, people all around the world will need access to testing and treatment to halt this scourge on a global level. Continue reading

STD Awareness: Can Older Adults Receive the HPV Vaccine?

female-patient-with-female-doctorWhen the human papillomavirus (HPV) vaccines were introduced, a lot of people were excited about protection from a sexually transmitted virus that could cause cancers, including cervical cancer, anal cancer, and head-and-neck cancer. It wasn’t just any old vaccine, it was a shot that could prevent cancer. Cancer!

In fact, a lot of people were disappointed they were too old to take advantage of an anti-cancer vaccine, which was initially approved for people as old as 26. We were given a lot of reasons why people above that age were “too old,” such as the assumption that anyone older than 26 has probably been sexually active for years and would have already contracted the most common strains of HPV.


While getting vaccinated before becoming sexually active is optimal, the HPV vaccine can still benefit people who have already had sex.


But there are compelling reasons to vaccinate people in their late 20s and beyond. In fact, Gardasil 9 was recently approved for people as old as 45. That’s great news for those of us who missed out on the HPV vaccine the first time around. We might never have had any sexual contact, and therefore were never at risk for catching the sexually transmitted virus. We might have found ourselves widowed or divorced after years or decades of monogamy. We might have been sexually active with multiple partners during that time. Whatever our circumstances, those of us who are 45 or younger can now consider HPV vaccination.

HPV and the “Older” Individual

When Cervarix and Gardasil, the first HPV vaccines, were released, they only protected against two cancer-causing HPV strains, HPV-16 and HPV-18, which are responsible for 70 percent of cervical cancers (Gardasil protects against two additional wart-causing HPV strains). A few years ago, Gardasil 9 hit the market, targeting five additional cancer-causing HPV strains — increasing the chances that even sexually active recipients could be protected from HPV strains they hadn’t encountered. Continue reading

STD Awareness: Eliminating HPV-Related Cancers

Earlier this month, every major cancer center and organization in the country released a joint statement calling for the elimination of cervical cancer, along with all other HPV-related cancers. The elimination of a large swath of cancers might sound like a tall order — so far, we’ve only eradicated two viruses from the planet: smallpox and rinderpest. And we’re on the brink of getting rid of a third, the virus that causes polio.

But doing away with human papillomavirus (HPV) would herald a new chapter in disease eradication, because HPV causes cancer, meaning that eradicating HPV will eradicate the cancers caused by it. And the good news is we have all the tools we need to wipe HPV off the face of the earth — we just need to use them.


The tools to wipe a large class of cancers off the face of the earth are right under our noses — we just have to use them.


A quick rundown on HPV is in order. It’s the most common sexually transmitted infection in the world, and causes multiple cancers — cervical, head and neck, anal, vulvar, vaginal, and penile. While it’s most well-known for causing cervical cancer, here in the United States it is transitioning away from its old job, causing more head-and-neck cancers than cervical cancers. Nearly all sexually active people will be infected with HPV at least once in their lives, and though only a fraction of infections progress to cancer, its ubiquity means it still causes hundreds of thousands of cancers every year. In the United States, around 41,000 HPV-related cancers are diagnosed annually, while more than 600,000 are diagnosed worldwide. Continue reading