Hepatitis A vaccine is an inactivated vaccine for injection. It is generally recommended that 2 doses should be administered with an intramuscular injection. In 95% of the population, antibodies are detectable 1 month following vaccination. The interval in between the 2 doses is from 6 to 12 months. After the second dose, nearly 100% of adults produce antibodies, with an average 20 years of protection.

Hepatitis A

Hepatitis A is an acute infectious disease. The feces of patients with hepatitis A are contagious in both latent and acute stages. Ingestion of water or food contaminated with hepatitis A virus can cause illness after an incubation period of 2 to 6 weeks.

Recommendations for Vaccination

For those who intend to work or travel in countries where hepatitis A is prevalent (e.g. Southeast Asia or China), it is recommended that blood samples be taken to check for adequate protective effect of hepatitis A antibodies. If there is a lack of antibodies, it is best to receive a dose of hepatitis A vaccine 1 month before departure, and the second dose should be received 6 to 12 months later. In early Taiwan society, as there was less emphasis on food hygiene, almost all the elderly had been infected with hepatitis A and are immune to it. In present day Taiwan, however, hepatitis A vaccine is recommended for people under 35 years of age because most people do not have antibodies and the vaccination is the most effective method to acquire immunity safely.

If you have chronic hepatitis B or C, whether you go to countries where hepatitis A is prevalent or not, it is recommended that hepatitis A vaccines be administered to protect the liver against additional harm in case of an acute infection. Because the current vaccines have good efficacy, it is not mandatory for antibody testing following vaccination.

Contraindications to Vaccination

Vaccination is contraindicated if you have high fever, are suffering from severe illnesses, are allergic to the hepatitis A vaccine (ingredients may include potassium aluminum sulfate, 2-phenoxyathanol), are infants under one year of age or are pregnancy (although no severe harm has been clearly established in pregnant women).

Possible Side Effects and Adverse Response After Vaccination

• After vaccination, please take a rest and observe for 30 minutes. If there is no discomfort, you may leave the hospital.
• Severe reactions are uncommon. However, there may be redness, swelling and pain at the inoculation site, with occasional fever and fatigue, which usually disappear within 1-2 days.
• If body temperature exceeds 38.5 ℃ and lasts for more than 2 days, please return to hospital for evaluation.

Reminders

• Please pay attention to the time of follow-up visit to complete vaccine.
• Hepatitis A vaccine: 2 doses.

Dose 2: administered 6 to 12 months after the first dose.

• After vaccination, please drink adequate water and get plenty of rest to reduce discomfort. If you have any questions, please return to the hospital.