Hepatitis B: Understanding Chronic Infection, Antiviral Treatment, and Vaccination

Chronic hepatitis B isn’t just a lab result-it’s a lifelong condition that can quietly damage your liver for decades before you feel any symptoms. If you’ve been told you’re HBsAg-positive for more than six months, you’re dealing with chronic hepatitis B virus (HBV) infection. This isn’t something you can outgrow or ignore. Left untreated, it can lead to cirrhosis, liver failure, or liver cancer. But the good news? We now have powerful tools to stop it in its tracks: effective antivirals and a vaccine that’s been saving lives for over 40 years.

What Makes Hepatitis B Chronic?

Not everyone who gets hepatitis B ends up with a chronic infection. Most healthy adults clear the virus on their own within six months. But about 5-10% of adults-and up to 90% of infants infected at birth-develop chronic hepatitis B. The difference? Your immune system’s ability to respond. In chronic cases, the virus hides inside liver cells, using a special form of its DNA called cccDNA to keep reproducing, even when blood tests look normal.

The diagnosis is simple: if the hepatitis B surface antigen (HBsAg) stays in your blood for six months or longer, you have chronic infection. But knowing you have it is only the first step. The real question is: is your liver under attack right now? That’s where HBV DNA levels, ALT (alanine aminotransferase), and fibrosis scans come in.

When Do You Need Treatment?

Treatment isn’t automatic for everyone with chronic HBV. Doctors look at three things: how much virus is in your blood (HBV DNA), whether your liver is inflamed (ALT levels), and how much scarring (fibrosis) has already happened.

Here’s what the latest guidelines say (2024-2025):

• If you have compensated cirrhosis (liver is scarred but still working), you start antivirals immediately-no matter your viral load or ALT.
• If you have decompensated cirrhosis (liver is failing), you need antivirals and should be evaluated for a liver transplant.
• For everyone else, the WHO 2024 guidelines now recommend treatment for anyone with HBV DNA over 2,000 IU/mL, even if ALT is normal and no scarring is seen. This is a major shift-no more waiting for liver damage to appear before acting.

Older guidelines, like AASLD 2018, were more restrictive. They wanted higher viral loads (over 20,000 IU/mL) and elevated ALT before treating. But newer data shows that even low-level replication can slowly harm the liver over time. Waiting means risking cancer decades later.

What Antivirals Work Best?

There are three main antivirals used today: tenofovir disoproxil fumarate (TDF), tenofovir alafenamide (TAF), and entecavir (ETV). Pegylated interferon is still used in rare cases, mostly in younger patients who want a time-limited course.

TAF (brand name VEMLIDY) is now the top choice for most people. Why? It works just as well as TDF at suppressing the virus-but it’s much gentler on your kidneys and bones. Studies show that switching from TDF to TAF improves kidney function and increases bone density within months. If you’re over 50, have high blood pressure, diabetes, or already have kidney issues, TAF is the safer bet.

Entecavir is also highly effective and has a strong resistance profile. But it’s not as forgiving if you miss doses. TAF and TDF have the highest barrier to resistance-you can miss a pill now and then and still be protected.

Here’s how they compare:

First-Line Antivirals for Chronic Hepatitis B

Drug	Brand Name	Key Benefit	Key Risk
Tenofovir alafenamide (TAF)	VEMLIDY	Highly effective, safe for kidneys and bones	Cost; requires ongoing monitoring
Tenofovir disoproxil fumarate (TDF)	Viread	Well-studied, affordable	Potential kidney toxicity, bone density loss
Entecavir (ETV)	Baraclude	Very low resistance rate	Less effective if you’ve had prior lamivudine treatment

Antivirals don’t cure hepatitis B-they control it. Most people need to take them for life. Stopping too soon can trigger a dangerous flare-up of liver inflammation. Your doctor will monitor your HBV DNA, ALT, and liver scans every 6-12 months. Some patients with very low viral loads and no scarring may be candidates for future finite treatment, but that’s still experimental.

What About Hepatitis D?

If you have chronic hepatitis B, you’re at risk for hepatitis D (HDV)-a virus that only infects people already carrying HBV. It’s rare in the U.S. but common in parts of Africa, the Amazon, and Eastern Europe. HDV makes liver disease progress faster and increases cancer risk.

Every HBsAg-positive person should be tested for HDV. It’s not optional. If you have both, your treatment plan changes. You’ll need stronger monitoring and possibly different antivirals. There’s no cure for HDV yet, but new drugs are in trials.

How Vaccination Stops the Spread

The hepatitis B vaccine is one of the most successful public health tools ever made. It’s safe, 95% effective, and gives lifelong protection for most people. It’s given in three doses over six months. Babies get their first dose at birth-this alone has cut mother-to-child transmission by over 90% in countries with strong programs.

If you’re an adult and never got vaccinated, it’s not too late. The CDC recommends it for everyone under 60, and for older adults with risk factors: diabetes, kidney disease, travel to high-prevalence areas, or having a partner with HBV.

For unvaccinated people exposed to infected blood or bodily fluids, there’s a two-part emergency plan: hepatitis B immune globulin (HBIG) and the first dose of the vaccine, given at the same time but in different arms. This combo is 85-95% effective at preventing infection if given within 24 hours.

Special Cases: Pregnancy, HIV, and Children

Pregnant women with high HBV DNA (over 5.3 log10 IU/mL) should start tenofovir at week 28 of pregnancy. This reduces the chance of passing the virus to the baby to less than 1%. The baby then gets HBIG and the first vaccine dose within 12 hours of birth. This combo is nearly 100% effective at preventing infection.

If you have HIV and HBV, you need antivirals that work against both viruses-tenofovir and emtricitabine (often in one pill like Truvada or Descovy). Don’t use drugs that only treat HIV; that can make HBV worse.

Children with chronic HBV need specialized care. The first national pediatric guidelines came out in 2018. Many kids don’t need treatment right away, but they need regular checkups. Some will clear the virus naturally as they grow. Others will need antivirals by adolescence.

What’s Next? The Future of Hepatitis B

Right now, antivirals suppress the virus but don’t eliminate it. The real goal is a functional cure-where the virus is gone from the liver, HBsAg disappears, and the immune system controls it without drugs.

Over 15 new drugs are in clinical trials targeting cccDNA, the hidden core of the virus. Some aim to turn off the virus’s ability to replicate. Others train your immune system to recognize and destroy infected cells. Experts predict that by 2030, 30-40% of people with chronic HBV could achieve a functional cure using combination therapies.

But until then, the best tools we have are simple: get tested, get treated if needed, and make sure everyone you know is vaccinated. The WHO wants to eliminate hepatitis B as a public health threat by 2030. That’s possible-but only if we use what we already have.

What Should You Do Right Now?

• If you’ve never been tested for HBV and you’re over 18, ask your doctor for a simple blood test.
• If you’re HBsAg-positive, see a liver specialist. Don’t rely on your GP alone-this needs expert management.
• If you’re on antivirals, never stop without talking to your doctor. Even if your liver feels fine, the virus is still there.
• If you’re pregnant and have HBV, tell your OB-GYN immediately. Treatment can protect your baby.
• If you’re unvaccinated, get the full three-dose series. It’s the best defense.

Chronic hepatitis B doesn’t have to be a death sentence. With the right care, you can live a full, healthy life. The tools are here. What matters now is using them.