Hepatitis A Vaccination （英文）

What is hepatitis A?

Hepatitis A is one type of viral hepatitis. In general, it is transmitted by eating contaminated and improperly cooked food, especially shellfish. Contaminated water or other beverages can also transmit the infection. Whereas hepatitis A is a relatively mild disease in children, it is more serious in adults, causing fever, fatigue, muscle pains, loss of appetite, nausea, diarrhoea, jaundice and tea-coloured urine. In a few cases, the liver may be severely affected but mortality due to hepatitis A is rare.

People who have been naturally infected are immune to the disease for the rest of their lives.

 

Is it a serious problem in Hong Kong

As sanitary standards and living conditions gradually improve, hepatitis A is no longer a common disease in Hong Kong. Cases of hepatitis A reported to the Department of Health average about a few hundred annually. Since the majority of those below 30 years of age have never been exposed to hepatitis A, a significant proportion of our population are susceptible. Under these circumstances, an epidemic of hepatitis A might easily occur if we happen to relax our hygiene standards.

 

How can we prevent hepatitis A?

To effectively prevent hepatitis A, you need to pay close attention to personal, food and environmental hygiene.

Personal hygiene-

• wash your hands before preparing or eating food
• remember to flush the toilet and wash your hands before you leave the restroom

Food hygiene-

• drink only boiled water
• all food, especially shellfish, should be thoroughly cleaned and well cooked. (The hepatitis A virus dies within five minutes at 100o C)
• do not contaminate cooked food with your unwashed hands or unclean water

 

Environmental hygiene-

• handle contaminated water and sewage properly
• store your drinking water in clean and properly topped containers to avoid contamination
• keep cooking utensils and tableware clean

In addition, vaccination against hepatitis A is effective in preventing the infection.

What is hepatitis A vaccination?

The hepatitis A vaccine is essentially an inactivated form of the virus, approved for use as a vaccine in people above 2 years of age. On injection into the deltoid muscle, the vaccine stimulates the production of antibodies against the hepatitis A virus. The success rate exceeds 94%. Many believe that the immunity which results can last for more than 10 years.

Do I need the hepatitis A vaccine?

To date there is no firm evidence to help decide who must get the vaccine. The following are some of the factors that you should consider before you decide whether the vaccine is appropriate for you.

• most people in Hong Kong who are above 40 have already been exposed to hepatitis A and therefore immune to the virus
• frequent travellers to places where hepatitis A is highly endemic run the risk of consuming contaminated water and food and getting infected
• people who have the habit of eating uncooked shellfish stand a higher chance of being infected
• date abroad indicate that homo-and bi-sexuality are risk factors of the infection
• infected workers of the food industry, eg. restaurant attendants and chefs, have the potential of spreading the infection if they are not careful with personal, food or environmental hygiene

How is the vaccine administered?

To induce immunity, the vaccine has to be administered twice, into the deltoid muscle. The second injection is given 6-12 months after the first.

How good is the protection offered by vaccination?

Vaccination takes one month before immunity appears, and it takes two injectionsto achieve a long-lasting effect. Protection against infection is good but also specific. No other infectious agent but hepatitis A is prevented. In fact, quite a few infections are transmitted in the same way as hepatitis A,eg. cholera, dysentery, typhoid, Salmonella food poisoning, and numerous parasites. To effectively prevent all of these infections, one must maintain good personal, food and environmental hygiene.

 

Where can I get the vaccination?

If you think that hepatitis A vaccination suits your needs, please ask your family doctor for arrangement of injections.

What if I think I have got hepatitis A?

If you suspect hepatitis A,

• Consult your doctor and consider blood tests
• Do not take over-the-counter medications without the doctor's advice
• Abstain from alcohol
• Be extra careful in maintaining your personal and food hygiene to avoid transmitting the infection to others