Hepatitis B & C Antivirals: One We Suppress, One We Cure
Two viruses attack the same organ, yet our drugs treat them in opposite ways. Hepatitis B we can suppress but rarely eliminate — a lifelong daily pill that keeps the virus quiet. Hepatitis C, once a slow road to cirrhosis, we now cure outright in a couple of months. The contrast is one of the most instructive stories in antiviral medicine.
A patient learns they carry hepatitis C, the virus that silently scars the liver over decades. A generation ago the news meant a punishing year of interferon injections with a coin-flip chance of success. Today it means twelve weeks of a well-tolerated tablet and a better than 95% chance of complete cure. Next door, a patient with hepatitis B gets different news: we can control your virus and protect your liver, but you'll take a pill every day, probably for life. Same organ, two viruses, two entirely different pharmacological stories.
Hepatitis C — the cure story
Direct-acting antivirals cure hepatitis C. Hepatitis C is an RNA virus, and — like HIV — its replication depends on specific viral enzymes. The revolution came with direct-acting antivirals (DAAs): drugs designed to block those enzymes precisely. They come in classes named for their target, and the drug names give them away — the '-previrs' block the viral protease, the '-asvirs' block a protein called NS5A, and the '-buvirs' block the viral polymerase (the RNA-copying enzyme). Modern treatment combines two or three of these into a single daily tablet (for example sofosbuvir with velpatasvir), taken for 8–12 weeks. Because the drugs hit several viral targets at once, resistance rarely gets a foothold, side effects are minimal, and cure — defined as no detectable virus months after stopping — exceeds 95%. Hepatitis C became the first chronic viral infection we can reliably eliminate with pills alone.
Hepatitis B — the suppression story
Hepatitis B we control, rarely cure. Hepatitis B is a different beast. It's a DNA virus that tucks a stable form of its genome (called cccDNA) safely inside the liver-cell nucleus — a reservoir our drugs can't reach. So we can silence the virus but seldom erase it. The mainstays are nucleos(t)ide analogues — tenofovir and entecavir — the same kind of false-building-block drugs used against HIV, which block the viral reverse transcriptase and drive the virus down to undetectable levels. They're potent, safe, and have a high barrier to resistance, but because they don't clear the hidden reservoir, treatment is usually lifelong; stopping often lets the virus rebound. The older option, pegylated interferon, boosts the immune response and is given for a fixed course, offering some patients a chance at durable control, but with far more side effects. The real triumph in hepatitis B, though, is prevention: a highly effective vaccine that stops infection before it starts.
And a word on ribavirin. Ribavirin is an older broad antiviral that was once central to hepatitis C therapy and still appears in some regimens and for other viruses. It's worth remembering for two things: it is strongly teratogenic (harmful to a fetus), so it must never be used in pregnancy and demands strict contraception, and it commonly causes a haemolytic anaemia. As DAAs took over, ribavirin's role in hepatitis C shrank dramatically.
- Hepatitis C (RNA virus): direct-acting antivirals (DAAs) CURE >95% in 8–12 weeks.
- DAA classes by suffix: -previr (protease), -asvir (NS5A), -buvir (polymerase); combined in one pill.
- Hepatitis B (DNA virus): tenofovir/entecavir SUPPRESS but rarely cure — usually lifelong.
- The cccDNA reservoir in the nucleus is why hepatitis B can't be eradicated by current drugs.
- A vaccine prevents hepatitis B; ribavirin is teratogenic and causes haemolytic anaemia.
Why cure C but only suppress B? It comes down to where each virus hides. Hepatitis C keeps all its machinery in the cytoplasm and copies its RNA continuously — block those enzymes long enough and every last virus is flushed out, so the infection is cured. Hepatitis B stashes a durable DNA template (cccDNA) inside the cell nucleus, out of the drugs' reach; you can silence the factory but the master blueprint survives, ready to restart if treatment stops. The lesson is general: whether an antiviral can cure depends not just on how well it blocks replication, but on whether the virus leaves a reservoir behind.
- Expecting to cure hepatitis B with nucleos(t)ide analogues — they suppress; treatment is usually lifelong.
- Using ribavirin in pregnancy — it is strongly teratogenic.
- Forgetting hepatitis B can be prevented entirely by vaccination.
- Stopping hepatitis B therapy abruptly — the virus (and liver inflammation) can flare.
Why can hepatitis C be cured but hepatitis B usually only suppressed?
- Hepatitis C: direct-acting antivirals (-previr/-asvir/-buvir) cure >95% in 8–12 weeks.
- Hepatitis B: tenofovir/entecavir suppress the virus but rarely cure — usually lifelong.
- The difference is the cccDNA reservoir B hides in the nucleus, beyond the drugs' reach.
- A vaccine prevents hepatitis B; ribavirin is teratogenic — never in pregnancy.
- Katzung BG. Basic & Clinical Pharmacology — Antiviral Agents (anti-hepatitis drugs).
- Brunton LL, et al. Goodman & Gilman's The Pharmacological Basis of Therapeutics — Antiviral agents.
- AASLD / EASL — Hepatitis B and Hepatitis C treatment guidelines.
- Rang HP, Dale MM, et al. Rang & Dale's Pharmacology — Antiviral drugs.
- Whalen K. Lippincott Illustrated Reviews: Pharmacology — Antiviral drugs.
