Vaccine-preventable diseases
Hepatitis A |
What is it?
Hepatitis A is a virus that causes an acute inflammation of the liver and is the most common form of all viral hepatitis. Hepatitis A is encountered frequently in the most disadvantaged geographical regions. Improvements in hygiene and sanitation have led to a reduction in the circulation of the virus, but not to its complete disappearance.
Symptoms
Hepatitis A is often asymptomatic in young children, and more severe in adults. After an incubation period of 15 to 45 days, the onset of the disease is marked by a sensation of generalized malaise including, fever, headache, muscle soreness, fatigue, and gastrointestinal disorders.It is often accompanied by jaundice, particularly in adults.
The condition may be long-lasting, with an acute phase of approximately one month and a convalescence phase of up to 6 months. (6)
No specific treatment is available.
Epidemiology and vaccination
Hepatitis A is a strictly human disease. Transmission occurs through the fecal-oral route, from person to person, or by ingestion of contaminated food or drinking water.
Approximately 1.4 million cases are reported each year, but the true incidence is thought to be 3 to 10 times higher due to the proportion of asymptomatic cases. (5)
Hepatitis A is most common in urban areas but the incidence rates differ according to geographical regions and socio-economic levels.
Hepatitis A vaccines are available.
References:
5 - Hepatitis A vaccines. WHO position paper. WER 2000, 75:37-44.
6 - Koff R.S. Clinical Manifestations and Diagnosis of Hepatitis-A Virus Infection. Vaccine 1992; 10 (suppl):S15-S17.
