Hepatitis A: It’s not simply “food poisoning”

Hepatitis A is a contagious liver infection caused by the hepatitis A virus (HAV), but it does not cause chronic disease.

While all forms of hepatitis affect the liver, hepatitis A behaves very differently from its more notorious cousins, hepatitis B and C. Unlike those chronic infections that can quietly damage the liver for decades, hepatitis A arrives suddenly, makes people miserable for a while, and then mostly disappears—leaving the infected community with lifelong immunity.

The Hepatitis A virus is exceptionally hardy, surviving on surfaces for weeks to months and resisting common disinfectants, acidic conditions, and freezing temperatures. This remarkable stability enables efficient transmission through contaminated food, water, and surfaces, requiring heat treatment at 85°C or chlorine bleach for effective inactivation.

Most people who get hepatitis A recover completely without any long-term liver damage. However, thinking of this viral infection as merely a mild illness is an oversimplification.

While many cases are mild, the infection can be severe and even fatal in adults over 50 years of age, people with weakened immunity, and preexisting liver disease.

Scientists have known about the condition we now call hepatitis A for centuries, though they originally called it “infectious jaundice” because of the characteristic yellowing of the skin it caused. 

It was not until the mid-20th century that they began to distinguish between different types of viruses that cause hepatitis. Hepatitis A became known as “infectious hepatitis” because it could spread easily from person to person, distinguishing it from hepatitis B, which was primarily transmitted through blood.

One major milestone was in 1973 when researchers finally identified the hepatitis A virus by examining stool samples from infected patients. With electron microscopes, scientists could finally see what the virus actually looked like—the same one that had been causing outbreaks for hundreds of years. 

This discovery led to the development of reliable blood tests by the mid-1970s, allowing doctors to definitively diagnose hepatitis A. 

The biggest breakthrough came in the 1990s with the introduction of a safe and effective vaccine, first approved in Europe in 1991 and in the United States in 1995. 

In the United States, for example, the impact was remarkable: countries that implemented routine vaccination programs saw hepatitis A rates drop by more than 95%, transforming what was once a common childhood illness into a largely preventable disease.

Globally, hepatitis A is most common in parts of the world with poor sanitation and limited access to clean water. In these regions, most children are infected at a young age when the illness is usually very mild or causes no symptoms at all. As a result, they develop lifelong immunity.

In countries with relatively good sanitation, such as the United States and Western Europe, overall infection rates are low. However, this means fewer adults have natural immunity, leaving them vulnerable to infection if they are exposed.

Who is at risk?

Recent outbreaks in developed nations highlight a shift in who is at risk. While travelers to endemic areas remain a key group, large outbreaks have occurred among specific populations, including:

• Travelers to endemic areas
• Adults over 40 years of age
• People experiencing homelessness
• People who use injection and non-injection drugs
• Men who have sex with men
• People with existing chronic liver disease

Outbreaks have also been linked to contaminated foods such as frozen berries and raw shellfish, imported from other countries, showing how easily the virus can travel across the globe in our interconnected food system.

Notable outbreaks

2025: Central Europe

• 2025: Austria: 87 cases and 3 deaths
• 2025: Czechia (Czech Republic): 600 cases and 6 deaths
• 2025: Hungary: 530 cases and no deaths reported
• 2025: Slovakia: 880 cases and no deaths reported

2016: United States

• 2016: United States (5 states): 51 cases and no deaths reported
  • Virginia: 44 cases
  • Maryland: 4 cases
  • North Carolina, Oregon, Wisconsin: 1 case each

Need reliable data on global hepatitis A outbreaks? The GIDEON infectious disease database has you covered.

Hepatitis A spreads through the fecal-oral route. This means the virus is passed from the stool of an infected person and enters another person’s body through the mouth. This can happen in several ways:

• Person-to-person contact: This is the most common way hepatitis A spreads in countries with good sanitation. It can happen in households, among sexual partners, or in any setting with close personal contact with an infected person.
• Contaminated food or water: An infected food handler who does not wash their hands properly after using the bathroom can spread the virus to the food they prepare. Eating raw shellfish from water contaminated with sewage is another source.
• Contaminated surfaces: The virus can survive on surfaces for several weeks. Touching a contaminated object and then touching your mouth can lead to infection.

People are most contagious with hepatitis A in the two weeks before they develop symptoms like jaundice (yellow skin and eyes), spreading the virus without realizing it.

Not everyone who gets hepatitis A will have symptoms. Young children, in particular, often have no symptoms at all, yet they can still spread the virus to others.

When hepatitis A symptoms do appear, usually about four weeks after exposure, they can come on suddenly and include:

• Fever
• Fatigue and a general feeling of being unwell (malaise)
• Loss of appetite
• Nausea and vomiting
• Abdominal pain, especially in the upper right side near the liver
• Dark-colored urine
• Clay-colored or pale stools
• Joint pain
• Jaundice (yellowing of the skin and eyes)

Symptoms typically last for less than two months, although some individuals may experience them for up to six months.

Doctors use a simple blood test to diagnose hepatitis A. While a physical exam might reveal jaundice or a tender liver, only blood work can confirm the diagnosis since hepatitis A symptoms are similar to many other illnesses, like the flu or food poisoning.

The blood test looks for specific antibodies the body produces to fight the virus. IgM (immunoglobulin M) antibodies indicate an active, current infection. IgG (immunoglobulin G) antibodies indicate that a past infection or vaccination has occurred, and immunity is now present.

There is no specific medication that cures hepatitis A. This viral infection is usually self-limiting, meaning it typically resolves on its own as the body’s immune system clears the virus. 

Treatment is typically focused on supportive care to help manage symptoms while your body recovers.

Supportive care includes:

• Rest: Fatigue is a major symptom, so getting enough rest is important
• Managing nausea: Eating small, frequent meals may be easier to tolerate than three large ones
• Staying hydrated: It is important to drink plenty of fluids, especially if you are vomiting
• Avoiding alcohol: Alcohol is processed by the liver, and you should avoid it completely during the illness to prevent further liver stress

While hepatitis A does not become a chronic illness, it is important to take it seriously. 

In rare cases, particularly in adults over 50 or people with pre-existing chronic liver disease (like hepatitis B, C, or fatty liver disease), hepatitis A can cause acute liver failure, a life-threatening condition that may require hospitalization or a liver transplant.

The best way to protect from hepatitis A is through vaccination. The hepatitis A vaccine is safe and highly effective.

The World Health Organization (WHO) recommends hepatitis A vaccination for people 12 months and older in countries where the disease is becoming more common among older children and adults. The vaccine is given as a two-dose series, with the second dose administered 6 to 18 months after the first.

In countries where hepatitis A is very common, almost all young children catch the virus naturally and develop lifelong protection, usually without feeling sick. In these places, widespread vaccination programs are not usually recommended because vaccinating only some children while others remain unvaccinated can create problems. 

The unvaccinated children from that community might not catch the natural infection anymore, leaving them with no protection at all. When these children become adults, they could get very sick from hepatitis A.

Studies show that the vaccine provides at least 15 years of protection, and likely even more, including lifelong immunity.

For specific vaccination recommendations in your area, check your country’s national public health policies, as guidelines may vary based on local disease patterns.

Hepatitis A is a preventable disease that is very different from its chronic counterparts, hepatitis B and C. While it typically resolves on its own without causing long-term damage, it should not be underestimated. The infection can cause significant illness and, in vulnerable individuals, can lead to severe complications.

In today’s world, hepatitis A is not just a concern for travelers. Outbreaks can occur anywhere, spread through close contact or contaminated food. Fortunately, we have powerful tools to fight it. Vaccination offers excellent, long-lasting protection, and practicing good hand hygiene remains a fundamental defense. 

By understanding the risks and taking preventive steps, we can protect ourselves and our communities from this ancient but still-relevant virus.

What are the first signs of hepatitis A?

The first signs of hepatitis A are often flu-like and can include a sudden onset of fever, fatigue, loss of appetite, and joint pain accompanied by nausea and stomach pain. Later, these are followed by more specific signs like dark urine, pale stools, and jaundice (yellowing of the skin and eyes).

How to cure hepatitis A?

There is no cure for hepatitis A. Treatment is supportive, focusing on rest, proper nutrition, and staying hydrated while your body’s immune system fights off and clears the virus on its own. It is also crucial to avoid alcohol to prevent additional stress on your liver. The best “cure” is prevention with the Hepatitis A vaccine.

How long does hepatitis A last?

Hepatitis A symptoms usually last less than 2 months, although some people can feel sick for as long as 6 months. People who get hepatitis A may feel sick for a few weeks or several months, but usually recover completely and do not have lasting liver damage. Unlike hepatitis B and C, hepatitis A does not cause chronic liver disease, and the infection clears completely from the body.

How long does the hepatitis A vaccine last?

The hepatitis A vaccine provides proven protection for at least 14 to 15 years, based on research. Additionally, mathematical models predict protection for 25+ years, and many experts believe it may be lifelong. The 14-15 year data simply reflects how long researchers have been able to follow their patients, not when immunity ends.

Is hepatitis A serious?

For most healthy people, especially children, hepatitis A is a mild illness that resolves completely. However, it can be much more serious in adults over 50 and in people who already have other liver diseases. In these groups, it can lead to severe complications, hospitalization, and in rare cases, acute liver failure, which can be fatal.

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