November 06, 2020

Hepatitis A: Risk Factors, Symptoms, Diagnosis, Treatment and Prevention

Hepatitis A refer to inflammation of the liver due to the hepatitis A virus (HAV). It tends to be a short-term (acute) illness; and is usually spread by eating or drinking something contaminated with the hepatitis A virus. It is more common in developing countries.

In this article:
What is hepatitis A?
How common is hepatitis A? And where is it commonly found?
How is hepatitis A transmitted?
What are the symptoms of hepatitis A?
Who is most at risk of getting infected with hepatitis A?
How is hepatitis A diagnosed?
Treatment of hepatitis A
Prevention of hepatitis A

What is hepatitis A?

Hepatitis A is a liver disease caused by the hepatitis A virus (HAV). The virus is primarily spread when an uninfected (and unvaccinated) person eats or drinks food or water that is contaminated with the faeces of an infected person. The disease is closely associated with unsafe water or food, inadequate sanitation, poor personal hygiene and oral-anal sex.

Unlike hepatitis B and C, hepatitis A does not cause chronic liver disease and is rarely fatal, but it can cause debilitating symptoms and fulminant hepatitis (acute liver failure), which is often fatal. Hepatitis A, however, have a lot in common with hepatitis E. Other virus types can also cause liver inflammation, including cytomegalovirus, Epstein-Barr virus, and yellow fever. Overall, the World Health Organization (WHO) estimated that in 2016, 7134 persons died from hepatitis A worldwide (accounting for 0.5% of the mortality due to viral hepatitis). Also see the separate articles on Hepatitis B, Hepatitis C, Hepatitis D, and Hepatitis E, for more details on the other viral hepatitis infections.

Hepatitis A occurs sporadically and in epidemics worldwide, with a tendency for cyclic recurrences. The hepatitis A virus is one of the most frequent causes of foodborne infection. Epidemics related to contaminated food or water can erupt explosively, such as the epidemic in Shanghai in 1988 that affected about 300 000 people. They can be also prolonged, affecting communities for months through person-to-person transmission. Hepatitis A viruses persist in the environment and can withstand food-production processes routinely used to inactivate and/or control bacterial pathogens.

The disease can lead to significant economic and social consequences in communities. It can take weeks or months for people recovering from the illness to return to work, school, or daily life. The impact on food establishments identified with the virus, and local productivity in general, can be substantial.

Abdominal organs, including the liver
Diagram showing abdominal organs, including the liver

How common is hepatitis A? And where is it commonly found?

Geographical distribution areas can be characterized as having high, intermediate or low levels of hepatitis A virus infection. However, infection does not mean disease because children infected young do not experience any noticeable symptoms.

Areas with high levels of infection

In low- and middle-income countries with poor sanitary conditions and hygienic practices, infection is common and most children (90%) have been infected with the hepatitis A virus before the age of 10 years, most often without symptoms. Epidemics are uncommon because older children and adults are generally immune. Symptomatic disease rates in these areas are low and outbreaks are rare.

Areas with low levels of infection

In high-income countries with good sanitary and hygienic conditions, infection rates are low. Disease may occur among adolescents and adults in high-risk groups, such as PWIDs (people who inject drugs), MSMs (men who have sex with men), people travelling to areas of high endemicity (high occurence), and in isolated populations, such as closed religious groups. In the United States of America, large outbreaks have been reported among homeless persons.

Areas with intermediate levels of infection

In middle-income countries, and regions where sanitary conditions are variable, children often escape infection in early childhood and reach adulthood without immunity. These improved economic and sanitary conditions may lead to accumulation of adults who have never been infected and who have no immunity. This higher susceptibility in older age groups may lead to higher disease rates and large outbreaks can occur in these communities.

How is hepatitis A transmitted?

The hepatitis A virus is transmitted primarily by the faecal-oral route; that is when an uninfected person ingests food or water that has been contaminated with the faeces of an infected person. In families, this may happen through dirty hands when an infected person prepares food for family members. Waterborne outbreaks, though infrequent, are usually associated with sewage-contaminated or inadequately treated water.

The virus can also be transmitted through close physical contact (such as oral-anal sex) with an infectious person, although casual contact (like hugging, shaking hands, etc) among people does not necessarily spread the virus if personal hygiene is observed.

What are the symptoms of hepatitis A?

The incubation period of hepatitis A is usually 14–28 days.

Symptoms of hepatitis A range from mild to severe, and can include fever, malaise (a feeling of being unwell), loss of appetite, diarrhoea, nausea, abdominal (tummy) discomfort, dark-coloured urine and jaundice (a yellowing of the skin and whites of the eyes). Not everyone who is infected will have all of the symptoms.

Adults have signs and symptoms of illness more often than children. The severity of disease and fatal outcomes are higher in older age groups. Infected children under 6 years of age do not usually experience noticeable symptoms, and only 10% develop jaundice. Among older children and adults, infection usually causes more severe symptoms, with jaundice occurring in more than 70% of cases. Hepatitis A sometimes relapses, i.e. the person who just recovered falls sick again with another acute episode. This is, however, normally followed by recovery.

Who is most at risk of getting infected with hepatitis A?

Anyone who has not been vaccinated or previously infected can get infected with hepatitis A virus. In areas where the virus is widespread (high endemicity), most hepatitis A infections occur during early childhood. Risk factors include:
  • poor sanitation;
  • lack of safe water;
  • living in a household with an infected person;
  • being a sexual partner of someone with acute hepatitis A infection;
  • use of recreational drugs;
  • sex between men;
  • travelling to areas of high endemicity without being immunized.

How is hepatitis A diagnosed?

Cases of hepatitis A are not clinically distinguishable from other types of acute viral hepatitis. Specific diagnosis is made by the detection of HAV-specific Immunoglobulin G (IgM) antibodies in the blood. Additional tests include reverse transcriptase polymerase chain reaction (RT-PCR) to detect the hepatitis A virus RNA and may require specialized laboratory facilities.

Treatment of hepatitis A

There is no specific treatment for hepatitis A. Recovery from symptoms following infection may be slow and may take several weeks or months. Most important is the avoidance of unnecessary medications. Acetaminophen / Paracetamol and medication against vomiting should not be given.

Hospitalization is unnecessary in the absence of acute liver failure. Therapy is aimed at maintaining comfort and adequate nutritional balance, including replacement of fluids that are lost from vomiting and diarrhea.

Prevention of hepatitis A

Improved sanitation, food safety and immunization are the most effective ways to combat hepatitis A.

The spread of hepatitis A can be reduced by:
  • adequate supplies of safe drinking water;
  • proper disposal of sewage within communities; and
  • personal hygiene practices such as regular hand-washing before meals and after going to the bathroom.
Several injectable inactivated hepatitis A vaccines are available internationally. All are similar in terms of how well they protect people from the virus and their side effects. No vaccine is licensed for children younger than 1 year of age. In China, a live attenuated vaccine is also available.

Nearly 100% of people develop protective levels of antibodies to the virus within 1 month after injection of a single dose of vaccine. Even after exposure to the virus, a single dose of the vaccine within 2 weeks of contact with the virus has protective effects. Still, manufacturers recommend 2 vaccine doses to ensure a longer-term protection of about 5 to 8 years after vaccination.

Millions of people have received injectable inactivated hepatitis A vaccine worldwide with no serious adverse events. The vaccine can be given as part of regular childhood immunization programmes and also with other vaccines for travellers.

Reference(s)
1). World Health Organization (July 2020). Hepatitis A. Available Online.
2). Centers for Disease Control (June 2020). Hepatitis A Information - FAQs, Statistics, Data, and Guidelines. Available Online.
3). Halliday ML, Kang LY, Zhou TK, Hu MD, Pan QC, Fu TY, Huang YS, Hu SL. An epidemic of hepatitis A attributable to the ingestion of raw clams in Shanghai, China. J Infect Dis. 1991 Nov;164(5):852-9. Available Online.
4). Jacobsen KH, Wiersma ST. Hepatitis A virus seroprevalence by age and world region, 1990 and 2005. Vaccine 28 (2010) 6653–6657. Available Online.

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