Why Do Newborns Need the Hepatitis B Vaccine?

The first vaccine a baby receives — within hours or days of birth — protects them from hepatitis B virus (HBV). In a lot of people’s minds, HBV is associated with drug use and sexual activity — which stigmatizes people who have been infected with HBV or are carriers of the virus. Unfortunately, this stigma causes a lot of people to question why babies even need to be vaccinated against it, often pointing to “Big Pharma” conspiracy theories. A lot of other people are put off by the misconception that the HBV vaccine is made with human blood (it’s not).


May is Hepatitis Awareness Month, a time to learn about a childhood vaccine that’s saved millions of lives.


There are perfectly good reasons to vaccinate babies against HBV, mainly that HBV is the leading cause of liver cancer, itself one of the Top 10 types of cancer worldwide. Nine out of 10 infants born to a mother who is an HBV carrier will develop chronic infections and become carriers themselves — and a quarter of them will die prematurely of liver disease. Babies who develop chronic HBV infections are 63 times more likely to develop liver cancer than non-carriers, a connection that is 2 to 3 times stronger than the link between smoking and lung cancer.

When it comes to HBV, age at infection matters. Most people with chronic HBV infections are exposed at birth or in early childhood, when they are most likely to develop chronic, lifelong infections — whereas only 2 to 6 percent of infected adults will develop chronic infections, with only 15 percent of them eventually dying from liver disease. The fact that chronic infection risk is inversely correlated with age at infection means that birth is the time when a child is the most vulnerable to this virus — hence the importance of vaccinating as early as possible. Continue reading

STD Awareness: The Surprising Sexual Transmission of Non-STDs

What is a sexually transmitted disease, or STD? If someone catches their partner’s cold during sex, is that cold an STD? According to the Office on Women’s Health, an STD is “an infection passed from one person to another person through sexual contact.” Unless the cold was passed through sexual contact, rather than mouth-to-mouth contact, it would not be considered an STD. Others say that, for an infection to be considered an STD, its sexual transmission must make it significantly more common in the population. So, a disease like the common cold would probably be just as common even if people never had sex.


MRSA, meningitis, and the virus that causes pinkeye can be transmitted sexually.


However, there are some infections, such as hepatitis C or bacterial vaginosis, whose status as official STDs is controversial. While researchers argue with one another over where to draw the line between an STD and a non-STD, let’s take a look at some bacteria and viruses that can be transmitted sexually, even though they’re not officially categorized as “STDs.”

MRSA: Methicillin-Resistant Staphylococcus aureus

MRSA bursting out of a dead blood cell. Image: Frank DeLeo, NIAID

MRSA bursting out of a dead blood cell. Image: Frank DeLeo, NIAID

You’ve probably heard of MRSA, which is pronounced “mersa” and stands for methicillin-resistant Staphylococcus aureus — a strain of bacteria that is resistant to every antibiotic in the penicillin family, as well as others. S. aureus, or “staph” for short, is the same bacteria responsible for TSS, or toxic shock syndrome, which has most infamously been associated with the use of highly absorbent tampons. But mostly, staph is a common cause of skin infections, which could be deadly in the pre-antibiotic era, but these days usually don’t raise too many eyebrows.

Unfortunately, with the emergence of MRSA, which is difficult to treat with the usual drugs, we might once again have to worry about minor skin infections blossoming into life-threatening conditions. Additionally, MRSA has found a way to hop from person to person via sexual contact, and sexually transmitted MRSA has been documented in both heterosexual and MSM (men who have sex with men) populations. Untreated, it can lead to a form of gangrene in which tissue blackens as it dies. Continue reading

STD Awareness: Shaving, Waxing, and Trimming, Oh My!

Last month, the connection between body-hair removal and sexually transmitted diseases (STDs) once again gave rise to a flurry of headlines. Media had previously reported on “studies” purporting that the popularity of waxing is leading to the extinction of pubic lice, or that shaving increases risk for a little-known STD called molluscum contagiosum.

The idea that waxing one’s nether regions is tantamount to habitat destruction for the lowly pubic louse makes a certain amount of sense. But was it really true that waxing was leading to diminished pubic-lice populations, or just a case of the media blowing an obscure medical factoid out of proportion? Ditto with the claims about molluscum contagiosum — though they were based on perfectly plausible premises, having to do with shaving causing microscopic skin injuries that create openings for infectious viruses, the average reader might not have been able to rely on a journalist’s ability to translate a scientific article from “medical-ese” into an easy-to-understand, yet fully nuanced, magazine blurb.


The case isn’t closed on the link between body-hair removal and STDs.


As we’ve written before, the reporting in the popular media left out important details — such as the fact that these weren’t studies at all, but rather educated guesses based on observations, published as letters to the editor. No one was comparing pubic lice infestations or sexually transmitted infections between groups of people with and without pubic hair.

Until now.

The medical journal Sexually Transmitted Infections recently published a study based on a survey of 7,470 American adults who had had at least one sexual partner. The salient point the media pounced on was that removing pubic hair increases STD risk by 400 percent: NPR screamed that “Going Bare Down There May Boost The Risk Of STDs,” Time proclaimed “Grooming is linked to a higher risk of STIs,” and The Guardian spooked readers with a rather tasteless piece about “the health dangers of bikini waxing.” Even Saturday Night Live’s Weekend Update got in on the action, albeit with a crude joke about old men’s genitals.

But let’s leave headlines behind and delve right into the medical journal itself. Continue reading

STD Awareness: Sexual Transmission of Zika Virus

Zika

Zika virus. Image: Cynthia Goldsmith, CDC

I first heard of Zika virus in an epidemiology class, when another student made on offhand remark: “Did you know Zika virus can be transmitted sexually?” Ever vigilant for material for the STD Awareness column, I excitedly scribbled the name of the virus in my notes. But upon further investigation, I found that there were only a couple of documented cases of the sexual transmission of this virus that no one had heard of, and decided there was no reason to freak people out about yet another potential STD when rates of more common STDs, like chlamydia and gonorrhea, were on the upswing.

A year later, Zika virus was splashed across headlines on a daily basis, mostly for its newfound association with birth defects, but also in light of revelations that it could be transmitted by sex.


Access to condoms and reliable contraception is more vital than ever.


While Zika virus is usually transmitted by mosquito bites, the discovery that it can be sexually transmitted made it the only known virus that could be spread both sexually and by mosquitoes. It’s also the only known mosquito-borne virus that can cross the placenta to harm a fetus. Like several other viruses, including CMV and rubella, Zika is implicated in serious birth defects. But many health authorities worry that its potential as a sexually transmitted pathogen is dangerously underestimated. As of August 31, there have been 23 confirmed sexually transmitted cases of Zika virus in the United States — but sexual transmission will rise as the virus jumps into local mosquitoes, which will also make it difficult or impossible to tell if a sexually active Zika patient got the virus from sex or directly from a mosquito.

Earlier this year, sexually transmitted Zika virus in Texas made headlines, with many journalists incorrectly proclaiming it the first known case of sexual transmission. In fact, Zika’s sexual transmission was first documented in 2008, before “Zika” was a household name and the married couple who published their experience in a scientific paper thought they could share their STD status in relative obscurity. Despite referring to themselves as “Patient 1” and “Patient 3,” a science reporter quickly figured it out and (with their permission) revealed their identities in a 2011 article — still years before Zika-bearing mosquitoes would hit the Americas and trigger a microcephaly epidemic that propelled the virus to infamy. Continue reading

STD Awareness: June Is National Congenital Cytomegalovirus Awareness Month

CMVPop quiz: Can you name the virus that most commonly infects developing fetuses when they are still in the womb?

Here’s a hint: June is National Congenital Cytomegalovirus Awareness Month.

In case that clue didn’t make it obvious enough, I’ll tell you the answer. The most common infection among developing fetuses is caused by a virus you might not have heard of: cytomegalovirus, or CMV. Around 30,000 children are born with this infection every year, and some of these babies will go on to develop serious problems because of it. National Congenital Cytomegalovirus Awareness Month is a time to learn about how CMV can affect pregnancy.


Cytomegalovirus can damage developing brain cells early in an embryo’s gestation.


This year, it might be of even greater interest, given the parallels that can be drawn between CMV and Zika virus, the emerging pathogen that has been dominating headlines lately. First of all, both CMV and Zika virus can be transmitted sexually, though they are not the first things you think of when the topic of STDs comes up, as they are overshadowed by more famous sexually transmitted viruses like herpes and human papillomavirus. While many of us are infected with CMV as children, we can also be infected as adults, often through sexual transmission — the virus can be found in cervical and vaginal secretions, saliva, and semen. The sexual transmission of Zika virus is not as well understood, but we know it can be found in semen, and there are documented cases of men passing the virus to sex partners through vaginal and anal intercourse. It might even be transmitted from a male to a partner by oral sex.

Second of all, both CMV and Zika virus are associated with birth defects. However, while the connection between CMV and birth defects has been known to us for decades, it was only in April that the Centers for Disease Control and Prevention concluded that Zika virus can cause fetal brain defects (though we’re still waiting for conclusive proof). Microcephaly is probably the most infamous of the birth defects associated with Zika virus, as well as CMV, but it’s not well defined. When you get down to it, though, microcephaly just refers to an abnormally small head, which itself might be indicative of a brain that has failed to develop fully. Continue reading

Hepatitis B Vaccine: The Importance of the Birth Dose

babiesDid you know that Saturday kicked off National Infant Immunization Week, which is part of a worldwide observance that shines the spotlight on the importance of vaccination? Most of us think of infant immunization as a tool to protect babies from childhood illnesses like chickenpox and whooping cough. But did you know that one infant immunization protects them from cancer later in life?

Globally, hepatitis B virus (HBV) is one of the top causes of cancer. Every year, it kills more than three-quarters of a million people worldwide. An HBV infection might be defeated by the immune system, but when it’s not, it can become a chronic infection. And chronic infections can lead to serious health outcomes, including cirrhosis and liver cancer. The younger you are, the less likely you’ll be able to fight off an HBV infection — 90 percent of infants infected with HBV will develop chronic infections, and 25 percent of them will go on to die prematurely after developing liver disease. Compare that to 2 to 6 percent of infected adults who will develop chronic infections.


Because infants are so vulnerable to developing chronic infections, vaccinating them against hepatitis B at birth makes sense.


Most people think of hepatitis as a bloodborne disease, and it is spread very efficiently when IV drug users share needles, during needle-stick accidents and other occupational injuries, or by using contaminated piercing needles, tattoo equipment, or acupuncture needles. Even sharing items like razors, toothbrushes, and nail clippers can do it, as the virus can survive outside of the human body for a week. HBV can also be spread by sexual contact, including vaginal and anal sex.

Lastly, babies and children can be at risk as the virus can be transmitted from mother to infant during birth, and during early childhood when risk of chronic infection is high. A significant number of people with chronic infections acquired them during early childhood, but we don’t know exactly how they got them, as their parents and other household contacts were negative for the virus or its antibodies. Since infants and children are at the highest risk for developing chronic infections, focusing on that population for prevention is very important.

Luckily, there’s a vaccine. Continue reading

Teen Talk: What Is Kissing Disease?

kissing diseaseIf you’re a total dork like me, you might have some plush microbes hanging out on your desk or in your bedroom. The one that represents Epstein-Barr virus is especially adorable (look to your right and try not to coo in delight!). I just want to grab it, cuddle up to it, and fall asleep in its pillowy purple-pink embrace.

In reality, Epstein-Barr virus, or EBV for short, is not the most warm-and-fuzzy microbe of the bunch. I’d way rather have a cold. Why? Because EBV causes mono, which is more whimsically known as the kissing disease. And, despite that cute moniker, kissing disease can be most unpleasant.


Take it from one mono survivor: “Mono stinks!”


First, an explanation of why mono is also called the kissing disease. Merely being in the presence of someone with mono won’t put you at risk, even if you’re both in the same room — you need to be actively swapping spit with them to be exposed to the virus. Kissing is probably the most famous way for two people to exchange saliva, but sharing cups, eating utensils, or toothbrushes can do it, too. After exposure to the virus, symptoms could show up in 4 to 6 weeks.

Second, an explanation of why mono can be so terrible. While not all teenagers and young adults who are infected with EBV will develop symptoms, those who do probably won’t enjoy the experience. Symptoms include extreme fatigue, head and body aches, sore throat, and fever. It’s bad enough to have those symptoms for a few days, but mono might seem to go on and on with no end in sight. Most people are better in 2 to 4 weeks, but even then it could take another few weeks to get back to 100 percent. And some unlucky people can experience these symptoms for six months or even longer! In addition to these nasty symptoms, serious complications are possible. Continue reading