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Diseases / Hepatitis A

Hepatitis A

What is it?: 

Hepatitis A is caused by the hepatitis A virus (HAV) which is transmitted primarily via the faecal/oral route either through ingestion of contaminated food and water or through direct contact with an infectious person. The incidence of hepatitis A is strongly correlated with socioeconomic indicators; with increasing incomes and access to clean water and adequate sanitation, the incidence of HAV infection decreases.1

Based on an ongoing reassessment of the global burden of hepatitis A, preliminary WHO estimates suggest an increase in the number of acute hepatitis A cases from 117 million in 1990 to 126 million in 2005 (and deaths due to hepatitis A to increase from 30 283 in 1990 to 35 245 in 2005). Increased numbers of cases were estimated to occur in the age groups 2–14 years and >30 years.1

Clinical features: 

Clinical features of hepatitis A are similar to those of other types of viral hepatitis. Typical signs and symptoms of hepatitis A include:2

  • Fever;
  • Malaise;
  • Loss of appetite;
  • Diarrhoea;
  • Nausea;
  • Abdominal discomfort; and
  • Jaundice (yellowing discolouration of the skin and sclera of the eyes, dark urine and pale stool).

Not everyone who is infected will have all of the symptoms. Adults have signs and symptoms of illness more often than children, and the severity of disease increases in older age groups. Recovery from symptoms following infection may be slow and may take several weeks or months.

Hepatitis A infection does not cause chronic liver disease and is rarely fatal, but it can cause debilitating symptoms and fulminant hepatitis (acute liver failure), which is associated with high fatality rates.

Mode of transmission: 

HAV is transmitted primarily by the faecal-oral route, that is, when an uninfected person contacts or ingests objects, food or water that has been contaminated with the faeces of an infected person. The virus can also be transmitted through close physical contact with an infectious person including sexual contact and not limited to anal-oral contact. Hepatitis A outbreaks among men who have sex with men have been reported. Waterborne outbreaks, though infrequent, are usually associated with sewage-contaminated or inadequately treated water.2

Incubation period: 

The incubation period of hepatitis A is usually 14 – 28 days.2

Prevention: 

Improved sanitation, food safety and immunisation are the most effective ways to combat hepatitis A. The spread of hepatitis A can be reduced by:2

  • adequate supplies of safe drinking water;
  • food safety practice;
  • proper disposal of sewage within communities.

On an individual level, infection risk can be reduced by observing:2

  • Personal hygiene
    • Wash hands properly with liquid soap and water before eating or handling food, and after going to the toilet or changing diapers.
  • Food hygiene
    • Drink only boiled water from the mains or bottled drinks from reliable sources.
    • Avoid drinks with ice of unknown origin.
    • Purchase fresh food from hygienic and reliable sources. Do not patronize illegal hawkers.
    • Eat only thoroughly cooked food.
    • Clean and wash food thoroughly. Scrub and rinse shellfish in clean water. Remove the viscera if appropriate. All shellfish should be thoroughly cooked before eating.
  • Environmental hygiene
    • Keep the premises and kitchen utensils clean
    • regularly clean and disinfect frequently touched surfaces such as furniture, toys and commonly shared items with 1:99 diluted household bleach
  • Hepatitis A vaccination
    • Hepatitis A vaccination is a safe and effective means to prevent the infection. Persons who are at increased risk for acquiring hepatitis A and persons with increased risk for severe adverse consequences should discuss with their doctors about hepatitis A vaccination for personal protection. According to the Scientific Committee on Vaccine Preventable Diseases, Centre for Health Protection, the following groups are recommended to have hepatitis A vaccination:
      • Travellers to endemic areas of hepatitis A
      • Persons with clotting factors disorders receiving plasma-derived replacement clotting factors
      • Persons with chronic liver diseases
      • Men who have sex with men
Managment: 

There is no specific treatment for hepatitis A. Therapy is aimed at maintaining comfort and adequate nutritional balance, including replacement of fluids that are lost from vomiting and diarrhoea.2

Reference:

  1. World Health Organization. Hepatitis A vaccines: WHO position paper. 2012.
  2. Centre for Health Protection. Hepatitis A. 19 August 2019. [ONLINE] https://www.chp.gov.hk/en/healthtopics/content/24/24.html Accessed on 29 Mar 2021.

 

MAT-HK-2100422-1.0-04/2021