Hepatitis A: Causes, Symptoms and Treatment

Hepatitis A is an infection of the liver caused by the hepatitis A virus (HAV). Spread through contaminated food and water or close person-to-person contact, the infection is a "one time" self-limited disease that rarely results in serious liver disease or death.

The hepatitis A virus is more prevalent in areas of low socioeconomic status where a lack of adequate sanitation and poor hygienic practices are common and children are often transmitters of the virus. Improvements in hygiene, public health policies and water supplies have greatly reduced the number of cases of hepatitis A worldwide.

Immunization against HAV virus has been available since 1995 and is now part of the childhood recommended immunization schedule.

Fast facts on hepatitis A

Here are some key points about hepatitis A. More detail and supporting information can be found in the main article.

• The hepatitis A virus was first identified in 1973
• Person-to-person contact is the most common means of transmission and is generally limited to close contacts
• Hepatitis A rates in the US have declined by 95% since the hepatitis A vaccine first became available in 1995
• In 2006, HAV vaccination was incorporated into the US routine childhood vaccination schedule
• Hepatitis A is the most frequent vaccine-preventable disease in travelers
• HAV is one of the most frequent causes of foodborne infection
• Virtually any food can be contaminated with HAV, particularly shellfish and vegetables
• Casual contact among people does not spread the virus
• Foodborne or waterborne HAV outbreaks are relatively uncommon in the US
• Improved sanitation and the HAV vaccine are the most effective ways to combat the disease
• In developing countries with poor sanitary conditions and hygienic practices, 90% of the population have often been infected with HAV before the age of 10 years
• The single most important factor that determines the severity of illness from HAV is age; those aged 50 and above have a higher chance of adverse events from the infection.

What is hepatitis A?

Hepatitis A is a virus that affects the liver and is most prevalent in areas with low standards of hygiene.

Hepatitis A is a virus that infects the liver, causing inflammation. The majority of infected adults develop symptoms 2 weeks after exposure.

Unlike hepatitis B and C, HAV infection does not cause chronic liver disease and is rarely fatal. People who have been infected become immune to HAV for the rest of their lives.

Hepatitis A has a worldwide distribution and is most prevalent in resource-poor regions where there is overcrowding, poor sanitation and a lack of reliable clean water resources. The virus survives for extended periods in seawater, fresh water, wastewater and soil.

Residents of Africa, Asia, and South America show nearly universal evidence of past infection. Exposure in early childhood is the norm in these regions, and most children never exhibit symptoms of the disease.

Causes of hepatitis A

The HAV is excreted in the stool (feces) of people with hepatitis A infection. The virus is transmitted from person-to-person through the fecal-oral route; that is when an uninfected person ingests food or water that has been contaminated with the feces of an infected person.

For the majority of hepatitis A infections, transmission occurs as a result of close personal contact with an infected household member or sex partner.

There are sporadic cases of foodborne hepatitis A outbreaks scattered across the US and are likely caused by HAV-infected food handlers who prepare food for a large social event (such as a wedding). A single HAV-infected food handler can transmit HAV to dozens or even hundreds of people and cause a substantial economic burden to public health.

HAV can remain infectious on environmental surfaces even after 1 month. The virus is killed by heating to over 185 °F (85 °C) for 1 minute. Adequate chlorination of water, as recommended in the US, kills any HAV that enters the water supply.

Risk factors for hepatitis A

The most common reported risk factor for hepatitis A in the US is international travel (up to 50% of cases), mainly to Mexico and Central and South America. Anyone who has not been vaccinated or previously infected can contract hepatitis A.

Others factors that increase the risk of developing hepatitis A infection include:

• Sexual and household contact with another person with hepatitis A
• Being a resident or staff in a small community residence setting
• Being a child or employee in a daycare center
• Homosexual activity in men
• Injectable drug use
• Exposure to food or waterborne outbreaks.

Routine vaccination of all infants began in 1999. In 2006, the Centers for Disease Control and Prevention (CDC) recommended expanding vaccination for all children in the US aged 12-23 months; this practice resulted in a 90% reduction in the number of cases of HAV infection. Infections will most likely occur in high-risk individuals or adolescents who missed the vaccination implementation.

Symptoms of hepatitis A

Hepatitis A symptoms include nausea, vomiting and abdominal pain.

The incubation period (the time from exposure to the onset of symptoms) for hepatitis A averages 30 days. Symptoms tend to come on suddenly, and range from very mild to severe, lasting up to 8 weeks.

Symptoms of hepatitis A include:

• Nausea
• Loss of appetite
• Vomiting
• Abdominal pain
• Diarrhea
• Fever
• Malaise
• Fatigue
• Joint pain
• Jaundice (a yellowing of the skin and whites of the eyes)
• Dark colored urine
• Pale stool color.

Approximately 75% of adults experience symptoms with infection, many with jaundice. Only 10% of those infected before the age of 2 will have symptoms.

Diagnosis of hepatitis A

Diagnosis of hepatitis A is made with a blood test. Both acute infection and past infection can be determined by the presence of certain antibodies in the blood.

Acute infections with HAV should be reported to local public health authorities to help prevent further spread of the disease. Imaging tests such as a CT scan or ultrasound are not typically used in routine cases of HAV infection.

Treatment for hepatitis A

There is no specific treatment for hepatitis A infection; therapy is generally supportive with an emphasis on maintaining comfort and preventing complications such as dehydration and exhaustion. Supportive care includes replenishing nutrition and fluids, avoidance of alcohol, rest and time off from work, and taking over-the-counter (OTC) pain relievers if needed.

Complications from infection are rare, and the majority of people who become ill with hepatitis A fully recover. Occasionally, hospital admission and intravenous (IV) fluids are required in those who experience significant nausea and vomiting.

Around 85% of HAV-infected individuals fully recover within 3 months, and nearly all have complete recovery by 6 months

Prevention of hepatitis A

Persons who have a known exposure to HAV should get immune globulin within 2 weeks of the exposure. Otherwise, immunization, good hygiene and safe food and water practices are all necessary interventions to help prevent the spread of hepatitis A infection.

Hepatitis A immunization

In 2006, The Advisory Committee on Immunization Practices (ACIP) of the CDC recommended routine HAV immunization of all children at 1 year of age.

The ACIP also recommend HAV vaccination for adults with the following risk factors:

• Individuals traveling to or working in countries with high or intermediate rates of HAV
• Individuals with chronic liver disease
• Individuals with clotting factor disorders
• Men who have sex with men
• Illicit drug users (injection and non-injection)
• Individuals with close personal contact with an international adoptee from a country of high or intermediate endemicity during the first 60 days following arrival in the US (household contact or regular babysitting, for example)
• Individuals working with HAV-infected primates or with HAV in a research laboratory
• Individuals with recent exposure to hepatitis A.

Vaccination consists of two doses of vaccine (given as a shot) spaced 6-12 months apart. Nearly 100% of people develop protective levels of antibodies to the virus within 1 month after a single dose of the vaccine, and the second dose acts as a booster.

Hygiene

Handwashing and safe food practices are effective in preventing hepatitis A transmission.

Good hygiene includes handwashing after using the bathroom, changing diapers and before preparing or eating food.

The hepatitis A virus may survive for up to 4 hours on the fingertips; handwashing is highly effective in preventing transmission as a result.

Environmental surfaces can be cleaned with a freshly prepared solution of 1:100 dilution of household bleach.

Safe food and water practices must be closely observed. International travelers should avoid raw shellfish, uncooked food and drinking from uncontrolled water sources. Commercially bottled water should be consumed. If that is not available, boiling water or adding iodine to the water will successfully destroy the virus.

Hepatitis A virus (HAV) infection is one of the most common viral infections worldwide. It has been declining in most parts of the world in recent decades, largely due to better living conditions and improved access to clean water and sanitation in underdeveloped countries.

The illness ranges in severity from mild to severe, with the majority of individuals fully recovering without complications. An effective vaccine against hepatitis A has been available since 1995 and is listed as a recommended childhood immunization. Other high-risk individuals should also be vaccinated.

Thorough and appropriately timed handwashing remains one of the most important personal behaviors for the prevention of hepatitis A virus infection.

References:

CDC, Viral hepatitis - hepatitis A information, accessed 25 March 2016.
Declining hepatitis A seroprevalence: a global review and analysis, KH Jacobsen and JS Koopman, Epidemiol Infect published December 2004, abstract.

Hepatitis A, Stephanie C. Brundage and A. Nicole Fitzpatrick, Am Fam Physician, published 15 June 2006.
Hepatitis A transmitted by food, Anthony E. Fiore, Clinical Infectious Diseases, doi: 10.1086/381671, published 2004.
Hepatitis A virus infections in the United States: model-based estimates and implications for childhood immunization, GL Armstrong and BP Bell, Pediatrics, published May 2002, abstract.
Medscape, Hepatitis A, accessed 25 March 2016.
UptoDate, Overview of hepatitis A virus infection in adults, accessed 25 March 2016.
World Health Organization, Hepatitis A, accessed 25 March 2016.