Hepatitis A is a highly contagious liver infection caused by the hepatitis A virus (HAV). Unlike hepatitis B and C, it does not cause chronic liver disease and most people recover completely within a few weeks to months. An estimated 100 million infections occur worldwide each year, leading to roughly 15,000 to 30,000 deaths, mostly in low- and middle-income countries across Africa and South Asia.
How Hepatitis A Spreads
The virus spreads through the fecal-oral route, which means you get it by swallowing something contaminated with the stool of an infected person. That sounds dramatic, but in practice it often comes down to everyday situations: eating food prepared by someone who didn’t wash their hands thoroughly, drinking contaminated water, or having close contact with an infected person.
Food is a major vehicle. Outbreaks have been traced to infected food handlers who touched items like salads, fresh fruit, sandwiches, pastry icing, and glazed baked goods. Fresh produce contaminated during growing or harvesting has also caused outbreaks, with frozen raspberries, strawberries, green onions, lettuce, and tomatoes all implicated over the years. Shellfish are another well-known source: oysters, clams, mussels, and cockles can concentrate the virus when they filter contaminated water.
The virus is remarkably tough. It can survive on surfaces and medical equipment for one to ten weeks depending on conditions, and it remains infectious at very low pH levels for over ten weeks. Waterborne outbreaks are rare in developed countries but have occurred through contaminated private wells and swimming pools, often linked to nearby septic systems.
Symptoms and Timeline
After exposure, symptoms typically appear in about 28 days, though the incubation period ranges from 15 to 50 days. This long gap means you can be infected and spreading the virus before you feel anything.
Early symptoms often resemble a stomach bug or the flu: fever, fatigue, loss of appetite, nausea, diarrhea, and abdominal discomfort. Within a few days to a week, the more distinctive signs of liver involvement show up. Your urine may turn noticeably dark, and jaundice can develop, turning the whites of your eyes and your skin yellow. These symptoms range from mild to severe, and not everyone gets all of them. Young children in particular often have mild or no symptoms at all, while adults tend to experience more noticeable illness.
Most people feel better within two months. However, 10 to 15 percent of cases involve relapsing symptoms that can drag on for up to six months. Even in those cases, the infection eventually clears on its own.
Who Faces the Greatest Risk
Hepatitis A tends to be more dangerous the older you are when you first encounter it. Adults over 40 face a higher risk of serious complications, and the mortality rate climbs to about 2.7 percent in adults over 50. People with existing chronic liver disease or weakened immune systems are also more vulnerable.
The most feared complication is fulminant hepatic failure, where the liver fails rapidly. This is rare, occurring in roughly 0.14 to 0.35 percent of hospitalized cases, but it can require an emergency liver transplant. The risk is highest in older patients and those who have been jaundiced for more than a week before developing confusion or other signs of brain involvement from liver failure.
How It’s Diagnosed
A blood test is the only way to confirm hepatitis A. Doctors look for a specific antibody called IgM anti-HAV, which your immune system produces during an active infection. This antibody shows up five to ten days before symptoms start and remains detectable for about six months.
A different antibody, IgG anti-HAV, appears around the time symptoms begin and stays in your blood for life. If a test finds IgG but not IgM, it means you had the infection in the past or were vaccinated, and you’re now immune. If both are present, you’re dealing with a current or very recent infection.
Treatment and Recovery
There is no antiviral medication for hepatitis A. Treatment is entirely supportive: rest, staying hydrated, and eating a balanced diet. Most people manage their recovery at home. Severe cases, particularly those involving persistent vomiting, dehydration, or signs of liver failure, may require hospitalization.
The good news is that hepatitis A does not become a chronic infection. Once your body clears the virus, you recover completely with no lasting liver damage, and you’re immune for life.
Vaccination
The hepatitis A vaccine is the most reliable form of protection. Children receive two doses: the first between 12 and 23 months of age, and the second at least six months later. Older children and teens who missed the vaccine as toddlers can still catch up. Infants aged 6 to 11 months traveling to areas where hepatitis A is common can get one early dose, though they’ll still need two more doses at the standard ages for long-term immunity.
Adults who haven’t been vaccinated can get the two-dose series at any age. This is especially worth considering if you’re traveling to regions with high rates of infection, if you have chronic liver disease, or if you’re in a group with elevated exposure risk.
What to Do After Exposure
If you’ve been exposed to someone with hepatitis A and you’re not vaccinated, there’s a narrow window to prevent the infection. The vaccine is effective as post-exposure protection when given within two weeks of contact. For people with weakened immune systems or chronic liver disease, doctors may recommend both the vaccine and an injection of immune globulin (a dose of concentrated antibodies) given at the same time in different locations on the body. The key is speed: the sooner you get the vaccine after exposure, the better your chances of avoiding illness entirely.