Hepatitis A is one type of viral hepatitis. It usually leads to acute hepatitis and jaundice.
- It has an incubation period usually 14-28 days.
- Most patients have a complete recovery. The liver may be severely affected in a few cases.
- Persons recovered from the infection develop lifelong immunity against the infection.
There is no chronic carrier state.
in Hong Kong
- Hong Kong is a region with low prevalence of hepatitis A.
- The recent outbreak in 1992 resulted in more than 3000 cases and 4 deaths.
- Annual reported cases of hepatitis A in Hong Kong fell from over 1000 in 1988 to only a few hundreds in recent years.
- Most of the people in Hong Kong below the age of 40 have never been infected.
of Hepatitis A
Hepatitis A is transmitted faeco-orally - the virus is transmitted from an infected person's stool to the water or food eaten by another person.
The virus can survive in water for more than a year and also in food for a few days, therefore it can be transmitted by:-
- eating contaminated food (especially shellfish like oysters, clams, cockles and mussels) without proper cooking;
- drinking contaminated water;
- close personal contact with infectious person, including sexual contact and not limited to anal-oral contact.
of Hepatitis A
To be careful with your personal, food and environmental hygiene.
- Personal hygiene - wash your hands with soap before preparing or eating food and also after going to the toilet.
- Food hygiene - drink only boiled water. All food, especially bivalve shellfish such as oysters, clams, mussels, and scallops, etc., should be carefully cleaned and thoroughly cooked.
- Environmental hygiene - treat contaminated water and sewage properly; store drinking water properly and keep all kitchen utensils clean.
Hepatitis A vaccine
Being vaccinated against hepatitis A helps to produce antibodies to the virus. A complete course of vaccination requires 2 injections, given 6 months to 12 months apart. The body takes 4 weeks to develop antibody against hepatitis A after the first vaccine injection.
Hepatitis A vaccine is not licensed for children younger than one year of age.
to consider before Hepatitis A Vaccination
As adults who are over 40 years old may already developed immunity against hepatitis A, hepatitis A serostatus should be checked before vaccination so as to avoid unnecessary injections.
Anyone who has ever had a severe life-threatening allergic reaction to the previous dose of hepatitis A vaccine or allergy to any vaccine component should not get another dose.
People who travel frequently to places with a high prevalence of hepatitis A will have a higher chance of getting infected.
People who frequently eat uncooked shellfish also have a higher chance of being infected.
Hepatitis A vaccine can be used to prevent infection, however, it does not substitute personal and food hygiene.
Data from abroad show that male homosexuals and bisexuals have a higher chance of being infected.
Infected food handlers stand the high chance of spreading the infection to others.
The safety of hepatitis A vaccine for pregnant women has not been determined, although there is no evidence that it is harmful to either pregnant women or their unborn babies. Pregnant women should preferably consult doctor for the appropriateness of hepatitis A vaccination.