Hepatitis A is a virus that causes infection and inflammation of the liver. It rarely results in serious liver damage or death and does not develop chronic liver disease.

Unlike hepatitis B or C, it does not lead to chronic liver disease, but it can result in significant loss of income and absence from work or school. Once a person has had it, they will have immunity. They will never be infected again.

The hepatitis A virus (HAV) is more common in areas of low socioeconomic status with a lack of adequate sanitation. It spreads through contaminated food and water or close person-to-person contact. Children often transmit it.

Improvements in hygiene, public health policies, water supplies, and, in 1995, the introduction of a vaccine, have reduced the number of cases worldwide.

However, outbreaks still occur. In December 2016, a multistate outbreak in the United States (U.S.) that affected 143 people was linked to a batch of frozen strawberries. There were no fatalities.

The Centers for Disease Control and Prevention (CDC) encourage vaccination to prevent infection and the spread of the disease.

Fast facts on hepatitis A virus:

  • The hepatitis A virus (HAV) was first identified in 1973.
  • HAV can be passed on between people or through contaminated food or water.
  • A person can have HAV without showing symptoms.
  • Infection rates in the United States (U.S.) have declined by over 95 percent since the HAV vaccine first became available in 1995.
  • In 2006, HAV vaccination was added to the routine childhood vaccination schedule in the U.S.
  • Foodborne or waterborne HAV outbreaks are relatively uncommon in the U.S.

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Hepatitis A is an acute viral infection that affects the liver.

Many people have no symptoms with HAV, but if symptoms appear, it is usually 15 to 50 days after infection. Most adults will experience symptoms similar to the flu.

These include:

  • nausea, loss of appetite, and vomiting
  • abdominal pain and diarrhea
  • fever
  • malaise and fatigue
  • joint pain
  • jaundice, a yellowing of the skin and whites of the eyes
  • dark-colored urine and pale stools

Children below the age of 6 years do not usually show symptoms.

Jaundice will affect:

  • fewer than 10 percent of children under the age of 6 years
  • from 40 to 50 percent of those aged 6 to 14 years
  • from 70 to 80 percent of people aged over 14 years

Symptoms often pass within 3 to 6 months of first being infected, but around 15 percent of people with HAV will have ongoing or recurring symptoms for 6 to 9 months.

HAV can be fatal in older patients and in someone who already has chronic liver disease.

A person with HAV will excrete the virus in the stool, or feces. It can be passed on when an uninfected person consumes food or water that has been contaminated with the feces of an infected person.

The virus can survive for a month or more in seawater, fresh water, wastewater, and soil.

Most infections are passed on through close personal contact with an infected household member or sex partner, not through casual contact.

Foodborne HAV outbreaks sometimes occur in the U.S., for example, through food handlers who have the virus. In 2016, an outbreak was traced to a batch of frozen strawberries.

The most common reported risk factor for HAV in the U.S. is international travel. Even among people staying in luxury hotels, 3 in every 1,000 acquire HAV each month.

Anyone who has not been vaccinated or previously infected is susceptible.

Others factors that increase the risk include:

  • sexual or household contact with an infected person
  • living or working in a community residence
  • attending or working in a daycare center
  • homosexual activity
  • injecting drugs, especially if sharing needles
  • other drug use
  • food handling
  • working with HAV-infected primates or with HAV in a research laboratory
  • exposure to food or waterborne outbreaks
  • people with clotting-factor disorders

In the U.S., routine vaccination of all infants began in 1999. In 2006, the CDC recommended expanding vaccination for all children in the U.S. aged 12 to 23 months.

This has resulted in a 95-percent reduction in the number of infections.

However, infection can affect those at a higher risk and adolescents who missed the vaccination implementation.

In places where there is no immunization, an outbreak can be explosive. In 1988, a single outbreak in Shanghai affected 300,000 people.

A blood test can confirm an infection with HAV. Antibodies can detect both acute infection and a past infection.

Acute infections with HAV should be reported to local public health authorities to help prevent the disease from spreading further.

There is no specific treatment, but supportive therapy can improve comfort levels and prevent complications such as dehydration and exhaustion.

This includes:

  • replenishing nutrition and fluids
  • avoiding alcohol
  • rest, with time off work
  • taking over-the-counter (OTC) pain relievers if needed

Patients with significant nausea and vomiting may be admitted to the hospital for intravenous (IV) fluids.

Complications are rare, and most people recover fully. Around 85 percent of people with HAV-infected recover fully within 3 months, and most people have complete recovery by 6 months.

Precautionary treatment after exposure

If a person has not been vaccinated, and they know they have been exposed to HAV, they can still receive either the vaccine or immune globulin within 2 weeks of the exposure.

This may include:

  • colleagues of a food handler who has tested positive for HAV
  • employees and children in a daycare center where someone has received a diagnosis of HAV
  • anyone in close personal contact with a person who has HAV, including nurses or carers

Which treatment they should receive will depend on the age and health status of the person.

    Prevention

      Prevention depends on immunization and good hygiene practices.

        Immunization

          The CDC recommends routine HAV immunization of:

          • all children at 1 year of age
          • adults who are at risk of exposure or who have chronic liver disorder

            Two doses of the vaccine are given as an injection, 6 to 12 months apart. Most people will have protective levels of antibodies within 1 month after a single dose. The second dose acts as a booster.

              Handwashing

                HAV can survive for up to 4 hours on the fingertips, so handwashing and safe food practices can help prevent transmission.

                  Handwashing should be done after using the bathroom, changing diapers, and before preparing or eating food.

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

                      Food and drink

                        Travelers should avoid raw shellfish, uncooked food, and food that may have been washed in contaminated water.

                          Drinking water should be commercially bottled or boiled to at least 185° Fahrenheit (F) or 85° Celsius (C) for at least 1 minute. Adding iodine to the water or treating it with chlorine will also kill the virus.

                            Takeaway

                              HAV is an acute infection that can affect the liver. It can last for several weeks or months.

                              The risk of getting it has reduced dramatically since the introduction of vaccinations.

                              People who are traveling to countries with a low socioeconomic status are advised to ensure they have the vaccination before they go.