New treatments have totally changed the game for people with hepatitis C. Taking a daily pill for a few months is often enough to cure the infection. But once the virus is gone, it might not be gone for good.

Hep C isn’t like chickenpox, where you get it once and then you’re immune for life. You can get hep C again if you’re exposed to the virus again.

Here’s a look at how reinfection works and what you can do to avoid it.

First, a primer on hep C. It’s a virus that spreads through blood-to-blood contact. Your blood has to touch the blood of someone who has the virus for you to get it.

Most people contract hep C by sharing needles or syringes to inject drugs. Less often, hep C spreads through a tattoo needle or ink that carries the virus, or during sex (especially anal sex) without condoms.

Why should you care about getting hep C more than once? Because it can cause heaps of complications if you don’t get treatment. We’re talking serious stuff like cirrhosis (liver scarring), liver failure, and liver cancer.

Since hep C can sneak in without symptoms, you might not know you have it. And you can’t get treatment if you have no idea you’ve got the virus.

Treating hepatitis C these days is pretty easy. You take a pill called a direct-acting antiviral (DAA) once a day. DAAs basically stop the virus from growing in your body.

These are some examples of DAAs:

  • elbasvir/grazoprevir (Zepatier)
  • ledipasvir/sofosbuvir (Harvoni)
  • glecaprevir/pibrentasvir (Mayvret)
  • sofosbuvir/velpatasvir (Epclusa)
  • sofosbuvir/velpatasvir/voxilaprevir (Vosevi)

After 8 to 12 weeks on one of these medications, the amount of virus in your blood should drop.

Around 95% of people who take DAAs have a sustained virologic response, which means there’s no sign of the hep C virus on a blood test. In other words, the infection is cured. Around 1 in 3 people clear the virus on their own — no medication needed.

But having hep C once and treating it doesn’t mean you’re immune to the virus. You can get hep C more than once. Doctors consider it a reinfection if you test positive for the virus after you’ve had two negative test results.

You could get a reinfection of hep C in the same way you contracted the virus the first time. Some factors that put you at risk are:

  • sharing needles and syringes when you inject drugs
  • having a sexually transmitted infection such as HIV
  • having sex with someone who has the virus without using a condom or another barrier method
  • getting a tattoo or piercing with a needle or ink that carries the virus
  • sharing a toothbrush, nail clippers, or another personal item that may have blood on it with someone who has the virus

The answer depends on which study you look at.

In some studies, the reinfection rate is as low as 1.7 reinfections per 100 person-years. (Researchers use the term “person-years” to describe the total amount of time every person contributed to the study.) In other studies, the rate is as high as 6.6 reinfections per 100 person years.

This range suggests that reinfection rates vary depending on behavioral factors.

People who keep injecting drugs after they’ve finished hep C treatment have the greatest risk of reinfection. The risk is also higher in men who have sex with men without using condoms and in people who are HIV-positive.

People who don’t inject drugs, have sex without condoms, or have any other risk factors have about a zero reinfection rate.

DAAs cure more hep C cases than older drugs such as ribavarin and interferon. But they also leave behind a bigger group of people who can contract the virus again.

To avoid a repeat of the hep C virus, avoid any possible contact with someone else’s blood. That means:

  • Don’t share needles, syringes, or any other equipment used to inject drugs. If you don’t have access to clean needles, you can get new ones for free through a syringe services program or needle exchange.
  • Check the licensing on the shop where you plan to get inked or pierced. Make sure they use clean needles AND ink on you.
  • Use a barrier method, such as a condom, every time you have sex with someone whose hep C status you don’t know.

If you’re not sure whether you’ve been exposed to hep C, there’s one way to find out: Get tested. Anyone who injects drugs and shares needles should get regular tests. Your doctor can let you know how often to get tested.

Hepatitis C isn’t a one-and-done kind of infection. Having the virus doesn’t make you immune to it for life.

To lower your risk of reinfection, use clean needles and syringes if you inject drugs, and use condoms when you have sex.

If you’ve had hep C before and think you may have it again, contact a healthcare professional and get tested. The sooner you know your hep C status, the sooner you can treat the virus to prevent damage to your liver.