Hepatitis A

Hepatitis A is an acute inflammation of the liver caused by the hepatitis A virus (HAV). It spreads through the fecal-oral route, meaning by swallowing water or food contaminated with the virus. It is the most common viral hepatitis and, at the same time, the most benign: in the great majority of people it clears on its own within a few weeks and the liver recovers completely.

The most reassuring point is that hepatitis A never becomes chronic. Unlike hepatitis B and hepatitis C, it leaves no virus living in the body and causes no long-term damage. It is also caught only once in a lifetime, because the infection leaves permanent immunity. Above all, it is a completely preventable disease, through hygiene and a very safe and effective vaccine.

How is it spread?

The virus is shed in the stool of an infected person and reaches others through the fecal-oral route. In practice this happens in several ways:

• Contaminated water or food, especially raw or undercooked shellfish and vegetables irrigated with sewage water.
• Person-to-person contact when hand hygiene is poor, particularly within the household and in nurseries or daycare centers.
• Sexual contact, particularly through practices involving oral-anal contact.

The incubation period (the time between exposure and the onset of illness) is 15 to 50 days. An infected person can spread the virus during the one to two weeks before jaundice appears, while still feeling well, which makes transmission easier.

What symptoms does it cause?

This depends greatly on age. In young children the infection often goes unnoticed or causes minimal complaints, so it frequently is not even diagnosed. In adults, by contrast, symptoms are more common and can be more intense. The most typical are:

• Nausea, loss of appetite and general malaise.
• Dark urine (the color of cola).
• Jaundice (yellow color of the skin and eyes).
• Discomfort in the right side of the abdomen and, sometimes, fever.

Most people recover within a few weeks. Some experience a relapse of symptoms after an apparent recovery, or a cholestatic form with intense itching and prolonged jaundice. Neither of these situations means a poor prognosis: hepatitis A does not last beyond about six months, and a chronic form does not exist.

Is it dangerous?

Generally not. The serious complication to be aware of is fulminant liver failure, a failure of the liver that may require a liver transplant. It is uncommon, fewer than 1% of cases, but the risk rises in two groups: adults, especially older ones, and people with pre-existing liver disease such as cirrhosis, hepatitis B or hepatitis C. This is why vaccinating those who already have liver disease is especially important.

It is wise to seek care promptly if persistent vomiting that prevents eating appears, or drowsiness and confusion, which can be signs of hepatic encephalopathy and warn of a severe course.

How is it diagnosed?

The diagnosis is confirmed with a blood test that detects the IgM anti-HAV antibody (immunoglobulin M against the hepatitis A virus), which indicates recent infection. It is usually accompanied by a marked rise in liver enzymes (AST and ALT), often above 1,000 U/L. The degree of enzyme elevation does not relate to severity. Bilirubin is usually high and is what explains the yellow color of the skin.

The test that best reflects severity is the prothrombin time: when it drops significantly, it signals that the liver is functioning poorly and calls for urgent evaluation.

How is it treated?

There is no specific antiviral treatment for hepatitis A, nor is one needed: the disease clears on its own. Management is supportive and aims to relieve symptoms while the liver recovers:

• Rest according to how the person feels. The long bed rest of the past is no longer prescribed.
• A light diet to reduce nausea, with less fat and fried food. No special diets are required.
• Good hydration, avoiding alcohol and unnecessary medications, which burden the liver.

Liver enzymes gradually decline over the course of one to two months. Only cases with fulminant liver failure require hospitalization and, occasionally, transplantation.

Prevention: hygiene and vaccine

Hepatitis A is prevented by acting on both ends of the problem. On one side, sanitary measures: safe drinking water, proper sewage management, food hygiene and frequent handwashing, especially after using the toilet and before cooking.

On the other, the vaccine, which is safe and highly effective. Its protection is long-lasting and nearly everyone who is vaccinated becomes immune. The World Health Organization recommends vaccinating the highest-risk groups and, in countries with intermediate endemicity, adding the vaccine to the childhood program. It is especially recommended for:

• People with chronic liver disease of any cause.
• Travelers to areas where the virus circulates widely.
• Men who have sex with men and others with higher-risk sexual practices.
• People who use drugs.

For those who had close contact with an infected person, the vaccine given within the first two weeks helps prevent infection (post-exposure prophylaxis). In certain cases immunoglobulin is also used.

Hepatitis A in Chile

Chile has moved from being a country where the virus circulated widely, with large outbreaks in the past, to one of intermediate endemicity, thanks to improvements in drinking water and sanitation. This progress has a less visible side: as fewer people are infected in childhood, more adults remain susceptible, and in them the disease tends to be more symptomatic and severe.

In recent years, outbreaks with sexual transmission among men who have sex with men have been described, a phenomenon also seen in other countries. In that setting, vaccinating high-risk groups is a key prevention tool. You can read more in hepatitis A outbreak in Chile.

See also

• What is hepatitis?
• Types of hepatitis
• Hepatitis A outbreak in Chile
• Jaundice