Some Good News About Three Sexually Transmitted Viruses

Scientists are hard at work finding ways to improve your health!

With so much bad news emblazoned across headlines in every newspaper you look at, the world might seem like a gloomy place. So let’s take one depressing subject — disease — and peel away the sad outer layer to find silver linings of optimism.

When it comes to infections, a lot of us blame one thing: germs, also known as “bugs” — “pathogens” if we’re fancy. Some people might not think of infectious diseases as being that big of a deal — after a round of antibiotics, you’ll be on the mend. Unfortunately, antibiotics only work for bacteria, but a lot of diseases are caused by other types of germs — for which antibiotics are no match. One type of germ is called a virus, and they can’t be cured. Sometimes they can be prevented with vaccines or treated with drugs. For example, the major strains of human papillomavirus (HPV) can be prevented with a vaccine called Gardasil, herpes simplex virus can be suppressed with antiviral drugs, and HIV can be controlled with antiretroviral drugs — but none of these infections can be cured. HPV is usually defeated by the immune system, but herpes and HIV are with you for life.

But it’s not all bad. Around the world, individual scientists have picked their “favorite” viruses and are devoting their lives to finding better prevention strategies, better treatments, and even cures. Let’s check in with some of the latest headlines touting the successes of science.

New Hope for a Herpes Vaccine

A herpes vaccine would be a blockbuster — given how common this sexually transmitted infection is, a preventive shot could help a lot of couples discuss their herpes status without as much fear of judgment and stigma.

Herpes might cause an “outbreak” — unpleasant symptoms that include genital sores — but afterward the virus goes dormant in the nerve cells, hiding from the immune system. In some people, the virus can come out of its dormancy to cause flare-ups of symptoms, but once it’s had its fun it retreats back to the nerve cells.

Earlier this year, media reported on a promising new candidate for a herpes vaccine. Using a completely different strategy than previous, failed herpes vaccines, the researchers behind this breakthrough targeted the part of the virus that allows it to hide from our immune systems. If this vaccine works as hoped, recipients will be able to mount an immune defense when exposed to the virus, blocking it from establishing a permanent home in nerve cells. It might even suppress outbreaks in people who already have herpes. Continue reading

STD Awareness: Genetics and the Gonococcus

Image: CDC

Ever since the discovery of effective antibacterial therapies less than a century ago, humans have been able to easily cure gonorrhea, the sexually transmitted scourge that laid waste to fallopian tubes and robbed newborns of vision. Most of us in the developed world have forgotten that this disease was once a leading cause of infertility in women and blindness in babies — and still is in much of the developing world.

Unfortunately, gonococci — the species of bacteria that cause gonorrhea — have been evolving resistance to every antibiotic we’ve thrown at them, including sulfonamides, penicillins, tetracyclines, macrolides, fluoroquinolones, and narrow-spectrum cephalosporins. We have one remaining first-line gonorrhea treatment left: extended-spectrum cephalosporins, which include cefixime, which is taken orally, and ceftriaxone, which is administered as a shot — and resistance is emerging to those drugs, as well.


Gonococci don’t swap potato salad recipes at family reunions — they swap genetic material!


The emergence of antibiotic-resistant gonorrhea is considered one of the most pressing problems in infectious disease — just two years ago, the Centers for Disease Control and Prevention named it an “urgent threat,” and indeed, gonorrhea seems to be evolving resistance to drugs at quite a rapid clip. Gonococci can acquire resistance to antibiotics in three ways.

First, a genetic mutation can endow bacteria with special antibiotic-fighting powers, making it harder for a drug like penicillin to attach to their cells and destroy them. Such a mutant is more likely to gain evolutionary traction if it finds itself in an antibiotic-drenched environment in which resistance to that drug allows it to “outcompete” other bacteria. Indeed, antibiotic resistance was first documented in the 1940s, just years after sulfonamides and penicillin were introduced as the first effective cures for gonorrhea. Continue reading

STD Awareness: The Next Generation of Gardasil Is Coming!

noisemakersIt’s January, which means it’s time to festoon our surroundings with streamers, throw around the confetti, break out the noisemakers, and shout Happy Cervical Health Awareness Month!

And, in 2015, we have something huge to celebrate: Last month, the Food and Drug Administration (FDA) approved Gardasil 9, the next-generation HPV vaccine, which provides broader protection than the current version. Next month, the new and improved vaccine will start to be shipped to health care providers, and the Advisory Committee on Immunization Practices is expected to give the Centers for Disease Control and Prevention the green light to recommend the vaccine, after which insurance plans and the Vaccines for Children program should start covering it.


The newest version of Gardasil protects against the seven strains of human papillomavirus that together cause 90 percent of cervical cancers.


Why is this news so exciting for people who care about cervical health? Because, while the current version of Gardasil, which debuted in 2006, protects recipients from the two HPV strains that cause 70 percent of cervical cancers, Gardasil 9 will protect against seven strains of HPV that collectively cause 90 percent of cervical cancers. On top of that, both versions of Gardasil protect against the two HPV strains that are together responsible for 90 percent of genital warts.

Gardasil 9 has been shown to be highly effective in clinical studies, and it is safe to use, which means Gardasil just became an even more potent weapon against cancers caused by HPV. Not only that, but vaccination against HPV will also reduce the frequency of precancerous lesions, which are cellular abnormalities that can be treated before progressing into full-fledged cancer. Less pre-cancer means less time, money, and anxiety spent dealing with followup procedures after an abnormal Pap test, for example. Continue reading

STD Awareness: The Herpes Virus and Herpes Medications

herpes medicationOne of the most common sexually transmitted diseases (STDs) is herpes, which affects an estimated 1 out of 6 Americans between the ages of 14 and 49. Herpes is caused by a virus, and one reason that it’s so widespread is that the herpesvirus is ancient. Prehistoric, even — dinosaurs are thought to have been infected by herpesviruses! The Herpesviridae family is huge, with at least 100 members infecting mammals, birds, reptiles, bony fish, amphibians, and oysters.


Herpes drugs from the acyclovir family physically block herpes DNA from replicating — which is pretty amazing!


Humans can suffer from both oral herpes and genital herpes, which are caused by two types of the herpes simplex virus (HSV-1 and HSV-2). Recent genetic analysis reveals that the virus that causes cold sores, HSV-1, has been evolving with us since before we were Homo sapiens, diverging from the viruses that infected our common ancestors 6 million years ago. Interestingly, we didn’t acquire HSV-2 — which mostly causes genital herpes — until our Homo erectus ancestors caught it from early chimpanzees 1.6 million years ago, well before the emergence of modern Homo sapiens around 200,000 years ago.

Most people know what the virus doesgenital herpes can involve blisters, pain, and itching — but most people don’t know how the virus works. Luckily, scientists have uncovered a lot of the virus’ secrets — which has allowed them to develop some pretty effective drugs that we can use to foil herpes’ plans. Continue reading

Are Pap Tests Accurate?

If you follow health news, you might have noticed some controversy over certain cancer-screening methods: Does the evidence support mammograms as a tool to reduce breast cancer deaths? Are PSA tests effective in saving lives from prostate cancer? These are questions that we are beginning to answer as more and more evidence comes in. But don’t let these questions dissuade you from all cancer screening.


With regular Pap testing, cervical cancer is almost 100 percent preventable.


In fact, although we’re reevaluating data for other cancer-screening methods, we have mountains of solid evidence that the Pap test is one of the best cancer-screening methods out there. Because it detects signature mutations that mark cells as headed toward becoming cancerous, Pap testing detects “pre” cancer while other cancer-screening techniques, like mammography, only detect cancer.

Cervical cancer used to be a top killer in developed nations — and it remains a major cause of death in countries without widespread health-care access — but in the last 50 years, cervical cancer deaths fell by 70 percent in the United States, transforming cervical cancer from the leading cause of cancer death among American women to a less common, nearly preventable cancer. Despite this, you might hear people complain that the Pap test isn’t accurate, citing the possibility of receiving “false positive” or “false negative” results.

A Pap test looks for abnormalities in cervical cells, and you can receive one of these four results:

True Positive: Cellular abnormalities are detected, and they are in fact present. True Negative: Cellular abnormalities are not detected, and in fact the cells are normal.
False Positive: Cellular abnormalities are detected, but the cells are actually normal. False Negative: Cellular abnormalities are not detected, but are actually present.

When we receive a true positive result, we can receive treatment for precancerous lesions that in fact might otherwise lead to cancer. Likewise, when we receive a true negative result, no further treatment is needed. Continue reading

How Does HIV Cause AIDS?

diagram of a human immunodeficiency virus

Last week, we gave a general background of human immunodeficiency virus (HIV), the virus that causes AIDS by destroying the immune system. But how is HIV able to disable our immune systems so effectively, anyway? The answer lies in its structure.

HIV, just like any other virus, is made up of a tiny capsule with a small piece of genetic code inside. While most viruses we’re familiar with store their genes on a molecule called DNA, HIV contains two pieces of RNA, which is another type of gene-storing molecule. The HIV capsules also contain an enzyme called transcriptase, which “translates” the RNA into a strand of DNA that our cells can read. Our cells are then tricked into reading this DNA and producing more copies of the virus — which are then released from the host cell, at which point they are free to infect other cells. In this manner, an HIV infection slowly grows.


HIV targets our immune systems, the very mechanism that evolved to keep us safe from pathogens.


When a virus is introduced into a host’s body, immune cells pick it up and carry it to the lymphoid organs — which are a sort of meeting place for other types of immune cells, including CD4+ T helper cells (also called helper T cells). Helper T cells enlist the help of other immune cells, called killer T cells, which destroy cells infected with viruses. Helper T cells also activate the production of antibodies, molecules that are specialized to attach to a specific pathogen so that it can be destroyed. Normally, this is where the virus meets its end. Unfortunately, HIV is different from run-of-the-mill viruses in that it is specialized to invade helper T cells. Now, instead of coordinating an attack against HIV, the helper T cells have been hijacked — converted into factories for the production of yet more HIV. Continue reading

How Often Do I Need a Pap Test?

Almost 80 years ago, Dr. George Papanicolaou developed a simple test, the Pap test (also called the Pap smear), done in a doctor’s office to check for cervical cancer. During a pelvic exam, a doctor swabs a small sample of cervical tissue and looks for abnormal cells. If these precancerous cells are detected, it will lead to more tests or other more invasive treatments such as a colposcopy (in which actual tissue may be removed). In the 1930s, when Papanicolaou was developing his test, cervical cancer was more lethal than breast cancer. But since the development of this test, the number of women dying from cervical cancer has dropped dramatically. In 2009, of the 4,000 women in the United States who died of cervical cancer, most had never been screened or had not been screened in the 10 years before their diagnosis.


This year, the U.S. Preventive Services Task Force recommended less frequent Pap testing.


Cervical cancer is most common in women between ages 35 and 55, and usually develops from a human papillomavirus or HPV infection. Not all HPV infections lead to cervical cancer, and it can take decades for a persistent infection with a high-risk type of HPV to become cancer. High-risk HPV types are sexually transmitted and can lead to cervical cancer and also anal, penile, and oral cancers.

There are two types of screening: Pap tests and HPV tests. While they both require a pelvic exam in which cells are taken from the cervix, Pap tests look for abnormal or precancerous cells, and HPV tests look for DNA or RNA from high-risk HPV types in cervical cells. Both tests are used to try to catch cervical cancer in its earliest stages so that it can be successfully treated. Continue reading