Hepatitis A & B (Combined) Vaccine (1 dose)

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Hepatitis A is a liver disease caused by the hepatitis A virus (HAV). Clinical features of hepatitis A are similar to those of other types of viral hepatitis. Typical signs and symptoms of hepatitis A include fever, malaise, loss of appetite, diarrhoea, nausea, abdominal discomfort, or 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 mortality. 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 (MSM) have been reported.  Waterborne outbreaks, though infrequent, are usually associated with sewage-contaminated or inadequately treated water. The incubation period of hepatitis A is usually 14 – 28 days.

Hepatitis B is another type of viral hepatitis that leads to acute hepatitis. It can be followed by chronic liver damage, including cirrhosis and liver cancer. It has an incubation period of 6 weeks to 6 months. About 5-10% of infected adults and 70-90% of infected infants are unable to clear the virus, therefore becoming chronic hepatitis B and serving as a source of infection to others. HBV infection occurs throughout the world. It is estimated that more than 2 billion people have been infected worldwide, of which more than 350 million have chronic liver infection. Hepatitis B is endemic in Southeast Asia. In Hong Kong, the overall prevalence of chronic hepatitis B infection is moderate. The hepatitis B virus is found in the body fluids of an infected person, mainly in the form of blood, amniotic fluid, semen and vaginal secretions. Routes of transmission include perinatal transmission, blood contact and sexual contact.