We know that hepatitis C is an increasing problem, and that it’s closely tied to intravenous drug use. But what is it, exactly? How does it work in your body? Let’s find out.
Hepatitis C kills more Americans than HIV and AIDS, and the number of people who are infected with the disease is growing. Dramatically.
In the last five years, the number of new hepatitis C infections has more than tripled — the U.S. Centers for Disease Control and Prevention estimates about 34,000 new infections in 2015. In 2014, the CDC estimated that between 2.7 and 3.9 million people in the U.S. had chronic hepatitis C.
New infections are increasing fast among people ages 20-30, mostly thanks to increasing use of injection drugs like heroin – the CDC estimates that about a third of injection drug users are infected with hepatitis C. And the CDC says growth of the virus among women of childbearing age is worrying because the virus can be passed from mothers to children.
But the group with the largest number of infected people? Baby boomers.
People born 1945-1965 are six times more likely to be infected with hepatitis C than are others, and their risk of dying from it is much higher.
In part, that’s because people who used injectable drugs in the 1970s and ’80s were much more likely to share needles. Medical practices around blood were substantially less stringent in the past, and blood transfusion was a major cause of hepatitis C infection prior to 1992, when blood screening for the disease became available.
The disease also takes a long time to develop: After an initial “acute” phase, when only 20 percent of people who are infected have symptoms, the disease becomes “chronic” in about 75 percent of cases, if not treated. And treatment only reduces the chance it becomes chronic. And once it does, it stays in the body, eventually causing long-term liver problems, chronic disease and, in some cases, death.
What hepatitis C does
Hepatitis C is bloodborne, and the most common way it’s transmitted is through IV drug use. It can also be transmitted through exposure to blood or to other body fluids that might have blood in them.
For a better understanding of how the disease works in the bodies of people who are infected, I turned to Dr. Robert Gish, a longtime researcher on hepatitis, a private consultant to liver transplant programs and a faculty member at the University of Nevada, Las Vegas, and Stanford University.
Why hepatitis C targets the liver
Gish says the body’s organs have specific receptors that viruses have evolved to recognize. For example, he says, the flu attaches to the lungs and the upper respiratory tract in your nose and throat. The hepatitis virus, on the other hand, “attaches the liver cells, and then once it’s in the liver cell it makes itself at home and builds little nests inside the liver cells to allow it to make millions and millions of viruses every minute, every hour, every day, because the liver has certain mechanisms that allow the hepatitis C virus to replicate, to reproduce.”
Like any living creature, hepatitis C has one main job: to make more of itself. And for the virus, the liver is the friendliest place to do that.
How hepatitis C endangers health
It’s worth noting again here that some people manage to oust hepatitis C from their systems while it’s still in the “acute” phase. Why does this happen? Gish says it’s mainly a matter of genetics.
“People have differences in their genes that allow a more vigorous immune response during acute infection. That vigorous immune response allows the immune system to kill every virus in the body,” he says.
But for those who don’t cure themselves the human body can coexist with some viruses — and in some cases they can be beneficial — but that’s not the case with hepatitis, and that has a lot to do with the response it provokes in our bodies. Once it gets comfortably ensconced in the liver cells, hepatitis C begins reproducing, and that attracts the attention of our immune system because it creates foreign proteins.
The immune system then attacks those cells to try to destroy the virus, and that can hurt or even kill those cells. The immune, or inflammatory, response also creates scar tissue, which, Gish says, can “make the liver cells leaky,” or kill them.
Lots of scar tissue on the liver has another name: cirrhosis. That can lead to liver failure, which means dialysis, a liver transplant or death.
The inflammatory response can also lead cells to eventually become cancerous: Once cirrhosis develops, the body’s efforts to repair the liver make it want to make more cells by dividing existing cells. Cancer is, basically, a disease in which cell division gets out of control, so any process where a great deal of cell division takes place creates a risk of cancer.
But Gish says that’s not all.
“It can also hurt the patient by causing a variety of other forms of tissue damage and organ damage. That’s because hepatitis C is present throughout the body, and can cause damage in the kidneys, brain, heart, eyes, lungs, nerves and others,” he says.
Gish says it’s linked to diabetes, vascular disease, stroke, kidney cancer, lymphatic cancer and other diseases.
The future of hepatitis C management
Gish says the state of treatment for hepatitis C is pretty good — if people get tested. Since hepatitis C doesn’t have any long-term symptoms, that’s an ongoing problem.
But for people who do, Gish says, “We now have treatment drugs that are extremely safe with cure rates between 95 and 100 percent with significant side effects being less than 1 percent.”
A vaccine doesn’t seem to be on the immediate horizon, though, Gish says. He says this is because the virus is “very clever” — it mutates at a very rapid rate and there are many, many variations, so it’s beyond our current vaccine technology.