Hepatitis A is a contagious liver disease that results from infection with the hepatitis A virus (HAV). Hepatitis A virus is found in the stool and blood of people who are infected. It can range in severity from a mild illness lasting a few weeks to a severe illness lasting several months. Hepatitis A is usually spread by eating or drinking food or water contaminated with the virus and sometimes by close personal contact. A person who has hepatitis A can easily pass the disease to others within the same household. Hepatitis A is a self-limited disease that does not result in chronic infection.

What are the symptoms and how does hepatitis A progress?

Signs and symptoms: The incubation period of hepatitis A is usually 14-28 days. More than 80% of adults with hepatitis A have symptoms, but the majority of children do not have symptoms or have an unrecognized infection. When symptoms are present, they usually occur abruptly and can include the following: fever, fatigue, loss of appetite, nausea, vomiting, abdominal pain, dark urine, clay-colored bowel movements, joint pain, and/or jaundice (a yellowing of the skin or eyes).

Disease progression: Symptoms usually last less than 2 months, although 10-15% of symptomatic persons have prolonged or relapsing disease for up to 6 months. Hepatitis A does not become chronic.

Who should get vaccinated against Hepatitis A?

Children:

• Hepatitis A vaccination is recommended for all children at age 1 year.

Adults:

• Travelers to countries that have a high rate of hepatitis A.
• People whose sex partners have hepatitis A, or people who have sexual contact with same-sex (homosexual).
• Users of injection and non-injection illegal drugs.
• People with chronic (lifelong) liver disease such as hepatitis B or hepatitis C.
• Persons who have clotting-factor disorders, hemophilia, and are treated with clotting-factor concentrates.
• People who have close household contact with someone infected with the hepatitis A virus.

How and when is the Hepatitis A vaccine series given?

• The hepatitis A vaccine is usually given intramuscularly into the deltoid or thigh muscle for 2 doses. The vaccine schedule as below;

Dose 1	Dose 2
At any given time	At least 6 month after first dose

 

• The hepatitis A vaccine also comes in a combination form, containing both hepatitis A and B vaccine, that can be given to persons 18 years of age and older. This form is given as 3 shots, on 0-, 1-, and 6-month schedule.
• More than 95% of recipients develop protective antibody levels within 2 to 4 weeks after the first injection. A second injection results in long-term protection.

 

Can a patient receive the first dose of hepatitis A vaccine from one manufacturer and the second (last) dose from another manufacturer?
Ideally, doses of vaccine in a series should be from the same manufacturer; however, if this is not possible or if the manufacturer of doses given previously is unknown, providers should administer the vaccine that they have available. The dose should be considered valid and does not need to be repeated.

 

What should be done if the second (last) dose of hepatitis A vaccine is delayed?

The second dose should be administered as soon as possible. The first dose does not need to be
re-administered.
 

Special precaution

Who should not receive the Hepatitis A vaccine or should wait?
The hepatitis A vaccine is not recommended for people who have had serious allergic reactions to a prior dose of hepatitis A vaccine, or to any part of the vaccine. Tell your doctor if you have any severe allergies. If you are moderately or severely ill when a dose of vaccine is scheduled, you should probably wait until you recover before getting the vaccine.
 

What are undesirable effects from hepatitis A vaccine?

Hepatitis A vaccine is safe. No serious side effects have resulted from the hepatitis A vaccine. Soreness at the injection site is the most common side effect reported. Mild systemic reactions, e.g. fever, malaise, and headache, are reported after vaccination around 3-4 hours and not last longer than 24 hours. However, the potential risks associated with hepatitis A are much greater than the potential risks associated with the hepatitis A vaccine.
 

Drug Interaction

Some medicines may interact with hepatitis A vaccine. Tell your health care provider if you are taking any other medicines, especially immunosuppressive therapy (e.g., cyclosporine) because it may decrease hepatitis A vaccine's effectiveness.
Hepatitis A vaccine could be administered concurrently with other vaccines e.g., hepatitis B, diphtheria, polio, tetanus, typhoid, cholera, Japanese encephalitis, rabies, and yellow fever vaccines.
 

References

• World Health Organization’s Media Centre. Hepatitis A: fact sheets. Geneva, Switzerland: World Health Organization; 2021 July. Fact sheet No. 328.
• Centers for Disease Control and Prevention. Hepatitis A. Available from: https://www.cdc.gov/hepatitis/hav/ [Accessed 1 November 2021].
• Full prescribing information for Havrix. Research Triangle Park, NC: GlaxoSmithKline group of companies (US); 2018 Dec. Document No.: HVX: 44PI.