Hepatitis A virus particles are pictured in this electron micrograph. Image: Betty Partin, CDC

Hepatitis isn’t commonly thought of as a sexually transmitted disease (STD) — for most people, hepatitis conjures images of contaminated food or unsanitary restaurants. But hepatitis should be on the radar of anyone who is sexually active. There are several different viruses that cause hepatitis, and some can be sexually transmitted, including hepatitis A (HAV), hepatitis B (HBV), and, to a lesser extent, hepatitis C (HCV).

While HBV is most efficiently transmitted through blood, it can also easily hitch rides from person to person via sexual fluids. However, we covered HBV in depth last year in observance of World Hepatitis Day. As May is Hepatitis Awareness Month, we’ll turn the spotlight on HAV and HCV for this month’s installment of our STD Awareness series.

Hepatitis A (HAV)

HAV spreads through fecal-oral contact and is more widespread in parts of the world with poor sanitation. It is relatively rare in the United States, although in 2003 there was a hepatitis A outbreak outside of Pittsburgh — the largest in the United States — that was traced to improperly washed raw scallions. All told, there were 650 confirmed illnesses and four deaths. HAV is very resilient and can survive outside a host for long periods of time — other foodstuffs it can contaminate include filter-feeding shellfish, which can concentrate HAV from contaminated seawater in their tissues. When these shellfish are undercooked, they can pack quite a punch as billions of virus particles are released into the unsuspecting diner’s body.

---

Vaccination against hepatitis A confers lifelong immunity while sparing you from illness caused by a natural infection.

---

Unfortunately, no matter how well you clean your fresh produce or how long you cook shellfish, certain sexual activities can increase your risk of acquiring HAV. As with intestinal parasites, which can be present in minuscule amounts of fecal matter, so too can virus particles be present in microscopic bits of feces. Oral contact with the anus (“rimming” or anilingus) is the riskiest activity in terms of HAV transmission — oral-genital contact can also do the trick, as can manual contact between the anus and the mouth. While hepatitis A outbreaks have been reported among MSM — men who have sex with men — populations, oral-anal contact is associated with increased risk for HAV infection regardless of sexual orientation. To reduce your risk of sexual HAV transmission, use latex condoms or dental dams during oral activities. HAV can also be transmitted via blood, and hepatitis A outbreaks have been reported among IV drug users.

Upon exposure, a host will incubate HAV for about four weeks before developing symptoms. These symptoms can vary, but they might include:

• low-grade fever
• headaches and muscle aches
• anorexia
• nausea or vomiting
• diarrhea
• dark urine
• jaundice

HAV can be fatal, though deaths only account for about 0.1 to 0.2 percent of cases.

Just before an HAV infection manifests as a disease, the virus is shed in abundance in the feces — at this time, an individual can be at his or her most infectious despite not yet being aware of infection. After the first two weeks of illness, infectiousness decreases. Luckily, unlike many other viruses, HAV does not become a chronic infection — once your immune system clears it, you’re immune for life.

This line graph shows the incidence of hepatitis A infections. A preventive vaccine was introduced in 1996. (Click to enlarge.) Graph: CDC

Being vaccinated against HAV, however, will confer lifelong immunity while saving you the trouble of illness and infectiousness. There is even a nifty combination vaccine that will protect you from both HAV and HBV. Vaccination is definitely worth looking into if you are at risk for exposure to these viruses. Sexual activities involving oral-anal contact can put you at risk, as can illicit drug use or simply traveling to a region where HAV is prevalent.

According to the Centers for Disease Control and Prevention, before the vaccine, HAV caused an estimated 200,000 to 300,000 infections annually in the United States. By 2009, there were less than an estimated 21,000 infections. It is currently recommended that children be vaccinated against both hepatitis A and B, but since these vaccines are relatively new, many sexually active adults have never been vaccinated.

Maurice Hilleman developed the vaccine by weakening HAV and killing it with formaldehyde. After successful animal tests, he ran a clinical trial in Kiryas Joel, a Hasidic enclave where 70 percent of residents were infected. This disproportionate HAV infection rate was due in part to a very high birth rate and crowded conditions among children, who bathed together in pools and ate from communal food at school. Uninfected children were split into two groups, one of which received the vaccine while the other received a placebo injection. Based on this small study, the vaccine was declared 100 percent effective. Merck licensed the vaccine in 1995 and it became available in 1996, after which the infection rate fell by 75 percent in the United States.

More information about hepatitis A virus can be found at the CDC’s website.

Hepatitis C virus, colored yellow in this transmission electron micrograph, is magnified approximately 100,000 times. Image: Thomas Deerinck, National Center for Microscopy and Imaging Research, UC San Diego

Hepatitis C (HCV)

HCV can be considered a sexually transmitted disease because, although it is not primarily transmitted sexually, the evidence shows that it can be. However, it is more strongly associated with the use of IV drugs.

Despite similar names, HAV and HCV aren’t closely related on a genetic level — they received their names based solely on their association with liver disease. Furthermore, while HAV is cleared by the immune system, 60 to 85 percent of HCV infections become chronic, and a lifelong infection can lead to liver damage, putting carriers at increased risk for cirrhosis, liver failure, and liver cancer. Additionally, while one can be vaccinated against hepatitis A and hepatitis B, there is currently no vaccine for hepatitis C.

---

Every year, hepatitis C causes more deaths in the United States than HIV.

---

Hepatitis C has surpassed HIV in terms of the number of deaths it causes every year in the United States. While this represents good news for the management of HIV as a chronic disease, it’s not good news for the estimated 3.2 million chronic carriers of HCV in the United States, most of whom are baby boomers. And because the infection is often asymptomatic — or has nonspecific symptoms, such as fatigue — in many cases it remains undiagnosed until it has wrought significant liver damage, a process that typically takes decades. HCV infection can be exacerbated by heavy drinking, obesity, insulin resistance, and HIV or HBV infection.

HCV is possible to transmit sexually, but it’s not spread this way as efficiently as are HAV and HBV. It is spread through contact with blood, so if your sexual activities are such that they could result in abrasions or cuts, it is especially important to be aware of blood-borne pathogens and how to protect yourself from them. However, even within relationships in which only one partner is HCV-positive, it is still quite rare for the virus to be transmitted.

Researchers have undertaken many studies to assess what sexual practices increase risk for HCV, but these studies haven’t always had consistent results. However, it seems that risk for sexual transmission of HCV might be correlated with:

• previous infections with syphilis or rectal gonorrhea
• anal intercourse
• lack of condom use
• a high number of sexual partners (defined as anywhere from five to 50 partners per year)

Some drug combinations have been known to cure HCV, with a 50 to 80 percent cure rate, and more pharmaceuticals are being developed. Treatment can be more difficult if patients have a history of drug or alcohol abuse. There is currently no vaccine for HCV, although researchers are working toward that goal.

More information about hepatitis C virus can be found at the CDC’s website.

Click here to check out other installments of our monthly STD Awareness series!