Hepatitis A infection is acquired primarily via the faecal-oral route by ingestion of food or water that has been contaminated with the faeces of an infected person. Common sources of infection include raw or partially cooked contaminated foods.

The virus can spread through close, personal contact with an infected person including caring for someone sick, or through certain sexual contact (e.g., oral-anal sex) or sharing illicit drugs with others.

People are most infectious 1 to 2 weeks before the onset of clinical signs and symptoms of jaundice or elevation of liver enzymes, when virus concentration is greatest in the stool and blood. Viral excretion and the risk for transmission diminish rapidly after liver dysfunction or symptoms appear

Incubation period: 28 days (range of 15 to 50 days).

Infectious period: 2 to 3 weeks before and 1 week after onset of jaundice.

Clinical features

Symptoms of hepatitis A range from mild to severe and can include:

Jaundice
Fatigue
Fever
Loss of appetite
Abdominal pain and tenderness
Nausea and vomiting
Pale-coloured stools and dark urine
Itchy skin

Risk factors

Although anyone can get hepatitis A, certain people are at a higher risk for infection and serious disease. These people include:

International travellers
Men who have sex with men
People who use or inject drugs
People whose jobs increase the risk of exposure
People who anticipate close personal contact with an international adoptee
People experiencing homelessness

Other conditions can also put people at a higher risk for developing serious disease from an infection, such as chronic liver and HIV.

Diagnosis

Hepatitis A infection is typically diagnosed by detecting the presence of Immunoglobulin M (IgM) antibodies against the hepatitis A virus (anti-HAV) in the blood.

Treatment and management

There is no specific anti-viral treatment for hepatitis A virus infection. Management is symptomatic and supportive. Consider referral to a hepatologist.

Precaution, prevention and control

Susceptible and medically eligible persons travelling to or working in countries that have high or intermediate hepatitis A endemicity should be vaccinated. The vaccine can also be administered as post exposure prophylaxis.

Foodborne hepatitis A outbreaks have been associated with contaminated food that are eaten uncooked or raw. Boiling or cooking food and beverages for at least 1 minute to 85°C inactivates the hepatitis A virus. Washing hands with soap and water after using the toilet, as well as before preparing and eating food, remains important.

Notification

Who should notify:

Laboratories

When to notify:

On laboratory confirmation

How to notify:

Please refer to the Infectious Disease Notification for more information.

Notification timeline:

As soon as possible. No later than 72 hours from the time of laboratory confirmation.

Resources

Please refer to the Weekly Infectious Diseases Bulletin for the number of confirmed acute hepatitis A cases in Singapore.