Pamela Anderson has announced she’s been cured of hepatitis C after living with the virus for 16 years.

The actress and model, 48, took to Instagram to share her good news. “I am CURED!!! - I just found out #nomorehepc," she wrote in the caption. "I pray anyone living with hep C can qualify or afford treatment. It will be more available soon. I know treatment is hard to get still...#dontlosehope.”

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Hepatitis C can be a debilitating and even fatal condition, but it can also be asymptomatic for years before it causes problems. That's why it can go entirely unnoticed for years. In fact, of the estimated 2.7 million people in the United States who have hep C, three in four don't know they're infected, according to the U.S. Centers for Disease Control and Prevention (CDC).

Many, many more people have never even heard of it. Below, we outline the need-to-know facts on the condition.

What exactly is Hepatitis C?

Hepatitis C is a blood-borne virus that causes inflammation of the liver. In some cases, people exposed to it (more later on how that happens) can fight it off on their own. But about 75% of people exposed go on to develop chronic infection, with many ultimately developing complications like chronic liver disease, liver failure, and liver cancer. Hepatitis C is the leading cause of liver transplants in the U.S.

How does Hepatitis C spread?

Like other blood-borne viruses, hepatitis C is spread through contact with infected blood. Anderson first went public with her diagnosis back in 2002, telling People in a statement at the time that she contracted it after sharing a tattoo needle with her then-husband Tommy Lee.

Sharing needles related to injection drug use is currently the most common way people contract it, per the CDC, but many people are also exposed at birth if their mother is infected or via accidental needle-sticks in hospitals or other healthcare settings.

Infection rates were highest in the 1970s and 1980s due to blood transfusions; there was no available hepatitis c blood screening test until 1992. The result: baby boomers, or people born between 1945 and 1975, are five times more likely to be infected. Blood banks now can screen for the virus, making the transmission risk from a transfusion extremely small.

Hepatitis C can also be transmitted through sexual activity if one partner is infected, though it's much less common.

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What makes hepatitis C so serious?

Unlike hepatitis B, another serious virus that affects the liver, there is no vaccination to prevent hepatitis C. It's also the most common blood-borne virus in the U.S., according to the Food and Drug Administration (FDA), and it kills roughly 15,000 Americans every year.

Referred to as a silent epidemic, it's also usually symptomless, and many people who have hepatitis C may even live for years without feeling sick—or may never feel effects at all, if they catch it before it advances. (The Baywatch star didn't experience symptoms: "I don't have any liver damage and I don't have any side effects," she told People in a previous interview.)

If an infected person does have symptoms, they can include fever, vomiting, abdominal pain, joint pain, dark urine, or jaundice (a yellowing of the skin and eyes).

Then how do you know if you have it?

The only way to know for sure is to get tested. Doctors use a blood test to scan for specific chemicals that the virus releases into the bloodstream. (Follow-up tests by your doctor would be the next step.)

The CDC made a big push in 2013 to educate baby boomers about the virus, and  encourage them to get tested. If you're never been tested, especially if you have risk factors like previous intravenous drug use, it can't hurt to talk to your doctor about it.

What's the connection between Hep C and HIV?

Both hepatitis C and human immunodeficiency virus (HIV) are blood-borne viruses that can be transmitted through injection drug use. Because of this, a high proportion of adults at risk of HIV may be at risk of infection for both diseases. According to the CDC, about a quarter of all HIV-positive people in the U.S. are "co-infected" with hepatitis C.

The hep C infection also tends to progress more quickly into liver damage in HIV-positive individuals.

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Can it really be cured?

Yes, it's now possible, but there are barriers. The FDA approved a pill that can cure hep C in December 2013, which has been considered a major medical breakthrough in recent years. Known as Sovaldi (sofosbuvir), the pill can cure up to an estimated 80 to 90% of Hep C patients in a matter of eight to 24 weeks when it's used in combination with another newer drug, Olysio (simeprevir), which was approved a month before Sovaldi.

However, the pill cocktail comes at an extremely high price, which has sparked a lot of controversy. For a full course of treatment of just one of the pills alone, it costs more than $80,000.

Anderson didn't disclose the exact drug treatment that she took to clear the virus, but she did raise an important point about how few people have access to the new treatments.

Will the drugs become more accessible in the future, as Anderson suggests? The answer is unclear, although drug companies and insurance providers appear to be working tirelessly to lower prices.

The New York Times explained in a September op-ed that government-run programs, like Medicaid, have placed certain restrictions on the drugs in an effort to control costs. For instance, some restrictions require that patients already have advanced liver disease before they can get the medication, or that the treatments can only be prescribed by specialists, like infectious disease experts.

This past June, the Presidential Advisory Council on HIV/AIDS Nancy Mahon penned a letter to the U.S. Department of Health and Human Services requesting to do away with restrictions that are denying people earlier treatment.

Prescription-assistance programs do exist; experts generally recommend that patients speak to their doctors about financial support and medication co-pay options.

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