What Is Hepatitis A: Virus, Transmission, and Prevention
Content last reviewed 2026-09-12 · Educational information — not medical advice
Quick answer
Hepatitis A is a liver infection caused by the hepatitis A virus (HAV), spread through the fecal-oral route — contaminated food, water, or close contact. Unlike hepatitis B and C, it never becomes chronic. A vaccine exists, and most people recover fully.
What is hepatitis A?
Hepatitis A is an infection of the liver caused by the hepatitis A virus (HAV). It's the most common type of viral hepatitis in terms of acute cases, and it behaves very differently from B and C: it never becomes chronic. The infection runs its course, the immune system clears it, and most people recover completely within a few weeks to months. Symptoms, when present, include fatigue, dark urine, jaundice, nausea, and upper-right belly pain. Recovery is usually complete with no lasting liver damage.
How is hepatitis A different from B and C?
Three big differences. First, transmission: hepatitis A spreads through the fecal-oral route (contaminated food, water, or close contact), not through blood or sex like B and C. Second, chronicity: hepatitis A never becomes chronic, while B and C can persist for life. Third, prevention: a highly effective vaccine exists for hepatitis A, just as it does for B — but not for C. These differences shape who gets tested, how, and why.
What are the symptoms of hepatitis A?
Symptoms usually appear 2-6 weeks after exposure and can include fatigue, dark urine, clay-colored stool, jaundice (yellow skin and eyes), nausea, vomiting, loss of appetite, and pain in the upper right abdomen. Many people, especially children, have mild or no symptoms. Adults are more likely to feel quite ill, and symptoms can linger for several weeks. Because symptoms overlap with other liver conditions, a blood test is needed to confirm the cause.
How is hepatitis A tested?
Testing looks for IgM antibodies to hepatitis A (IgM anti-HAV), which appear during an acute infection and are reliable about 2-4 weeks after exposure. A positive IgM result means a current or recent infection. Total anti-HAV (including IgG) shows past infection or vaccination, which is what immunity checks measure. If you've been exposed recently, timing matters — testing too early can miss the antibody window.
Can hepatitis A be prevented?
Yes, on two fronts. The hepatitis A vaccine is safe, effective, and recommended for all children plus adults at risk — travelers, people with chronic liver disease, and people in close contact with infected individuals. Beyond vaccination, good hand hygiene and safe food and water practices cut transmission dramatically, since the virus spreads through the fecal-oral route. Together these measures have made hepatitis A largely preventable.
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Frequently asked questions
Is hepatitis A an STD?
Hepatitis A is primarily foodborne, but it can spread through certain sexual practices involving oral-anal contact. It's not considered a classic STI.
Does hepatitis A cause chronic liver disease?
No. Hepatitis A never becomes chronic and doesn't cause long-term liver damage like hepatitis B or C can. Most people recover fully within a few months.