Symptoms do not occur in all people. (1)
- children <5 years - 80-95% of infections are asymptomatic
- in adults - 70-95% of infections result in clinical illness
- severity of symptoms also increases with age
The course of acute hepatitis A can be typically divided into four clinical phases (1,2,3):
- incubation phase or pre clinical period (during which time the virus replicates in the liver and is shed into the faeces)
- average incubation period is 28 days (range of 15-50 days)
- patient is asymptomatic but transmissibility is of greatest concern
- prodromal or pre-icteric phase
- may last from several days to couple of weeks
- typically, there are non-specific flu like symptoms (malaise, myalgia, fatigue) and mild fever. There can be non-specific gastrointestinal symptoms like loss of appetite, fatigue, abdominal pain, nausea and vomiting
- other symptoms like cough, pharyngitis, constipation, diarrhoea
- icteric phase
- jaundice develops (with associated anorexia, nausea and fatigue)
- usually lasts 1-3 weeks, in a minority of patients with cholestatic symptoms (itching and deep jaundice) - may last for 12 or more weeks
- dark urine and pale stools (before onset of jaundice)
- tender hepatomegaly
- pruritus
- fever is not present during this phase
- fulminant hepatitis may occur rarely (<1%)
- convalescent period
- resolution of the disease occurs
- malaise, tenderness and minor abnormalities of hepatic function may persist
The hepatitis is usually mild. In children, it is frequently, sub-clinical and only 10% of infected children develop jaundice. Adults tend to experience more serious and prolonged disease.
Faecal excretion of the virus declines once infection becomes asymptomatic.
Reference:
- Castaneda D, Gonzalez AJ, Alomari M, et al; From hepatitis A to E: A critical review of viral hepatitis. World J Gastroenterol. 2021 Apr 28;27(16):1691-1715.
- Committee on Infectious Diseases, American Academy of Pediatrics; Kimberlin D, Barnett E, Lynfield R, et al. Hepatitis A. In: Red Book: 2021–2024 report of the Committee on Infectious Diseases. 32nd ed. Elk Grove Village, IL: American Academy of Pediatrics; 2021.
- World Health Organization. Hepatitis A. July 2023 [internet publication].