Symptoms and disease progression

Hepatitis A has an incubation period of between 15 and 50 days between infection and the development of symptoms. The hepatitis A virus replicates in liver cells, but liver injury is due to the body's immune response rather the direct activity of the virus itself.

Most infants and young children have asymptomatic or mild disease, but the severity of illness increases with age. A majority of older children and adults experience symptoms, which may include:

• Feeling unwell.

• Fatigue.

• Nausea and vomiting.

• Diarrhoea.

• Loss of appetite.

• Fever.

• Upper abdominal pain.

• Muscle and joint aches.

After these initial symptoms, about 70% of older children and adults develop jaundice (yellowing of the skin and eyes) and about 80% experience hepatomegaly (liver enlargement).

Hepatitis A almost always clears up spontaneously. About 85% of infected individuals experience complete clinical recovery and normalisation of liver enzyme levels within three months, and most of the rest fully recover by six months.¹ Unlike hepatitis B and C, hepatitis A does not become chronic or lead to long-term liver damage such as cirrhosis or liver cancer. Once a person has had hepatitis A, they will not get it again.