HEPATITIS A OVERVIEW
Hepatitis is a common form of liver injury that simply means "inflammation of the liver" (the suffix "itis" means inflammation and "hepa" means liver). Hepatitis A is a specific type of hepatitis that is caused by a virus.
Hepatitis A virus (HAV) infection occurs worldwide. The number of people who become infected with HAV in the United States has declined substantially since a vaccine became available; the vaccine is routinely recommended for all infants and any adult who is at high risk of becoming infected. In 2005, 1.5 people per 100,000 were infected with HAV; this is the lowest infection rate ever recorded .
However, the infection rate is much higher in developing countries. Among travelers to developing countries, about three in every 1,000 travelers staying in luxury hotels acquire hepatitis A every month, and about 20 in every 1,000 travelers who eat or drink in poor hygienic conditions acquire hepatitis A every month.
This topic review discusses how hepatitis A is spread, the signs and symptoms of HAV infection, how it is diagnosed and treated, and how it can be prevented. Other types of hepatitis are discussed separately. (See "Patient information: Hepatitis B (Beyond the Basics)" and "Patient information: Hepatitis C (Beyond the Basics)".)
HOW DID I BECOME INFECTED WITH HEPATITIS A?
The hepatitis A virus is carried in the stool of infected people. The most common way for the virus to be spread is when an infected person does not wash their hands after using the bathroom and then touches food, a surface, or another person's mouth.
Hepatitis A virus is more common in areas that lack adequate sanitation or have poor hygiene practices. The majority of people who acquire the illness have had personal contact with an infected person.
Community outbreaks have occurred as a result of drinking contaminated well water or eating contaminated food. In one report, hepatitis A virus was detected in well water six months after the initial contamination . Hepatitis A virus can be acquired from contaminated food, usually raw shellfish that is harvested from contaminated water. Several outbreaks occurred as a result of eating contaminated green onions, which were imported from Mexico .
HEPATITIS A SYMPTOMS
Hepatitis A virus usually causes a sudden and short-lived illness. The severity of symptoms depends upon the person's age; in children, there may be few or no symptoms. In adults, infection usually causes a mild flu-like illness. Less commonly in adults, hepatitis A virus infection causes liver failure, which can lead to death.
The time from infection to the development of symptoms is approximately 30 days, with a range of 15 to 49 days. Initial symptoms usually include fatigue, feeling run down, nausea, vomiting, lack of appetite, fever (temperature greater than 100.4º F or 38º C), and pain under the ribs on the right side of the abdomen (where the liver is located) (figure 1). As the illness progresses, other signs and symptoms develop, including dark-colored urine, light colored stools, yellow colored skin or whites of the eyes (jaundice), and itchy skin.
HEPATITIS A DIAGNOSIS
A person is diagnosed with hepatitis A virus based upon their signs or symptoms, a physical examination, and blood testing. The blood test becomes positive about 5 days before symptoms appear and remains positive for about six months after infection.
HEPATITIS A TREATMENT
There is no cure for hepatitis A virus, although most people recover with supportive treatments at home, including rest. The amount of time needed to recover depends upon the individual; in general, the person should not return to work or school until the fever and jaundice have resolved and the appetite has returned.
During the recovery period, it is important to avoid drinking alcohol and taking certain prescription and over-the-counter medications (eg, acetaminophen/Tylenol®), which can injure the liver. People who drink alcohol on a regular basis (eg, seven to 14 drinks per week) should never take acetaminophen, even if they have not been infected with hepatitis, due to the risk of liver injury.
Less commonly, people infected with hepatitis A virus require treatment in a hospital to monitor the liver function, manage complications such as bleeding, provide adequate nutrition, and in rare cases, perform liver transplantation.
HEPATITIS A COMPLICATIONS
Most people feel better within three months of becoming infected with hepatitis A virus, and almost everyone completely recovers within six months. About 15 percent of people infected with hepatitis A virus will have prolonged or relapsing symptoms during the first six to nine months after being infected.
The most serious complication of hepatitis A virus infection is death. This occurs rarely, but is more likely in adults with chronic liver infections such as hepatitis C and those who are elderly. Children die as a result of hepatitis A virus in less than 0.1 percent of cases. (See "Patient information: Hepatitis C (Beyond the Basics)".)
Unlike with other forms of hepatitis, people with hepatitis A do not develop chronic liver disease as a result of their infection. Once a person is infected with hepatitis A virus, it is not possible to become infected again.
HEPATITIS A PREVENTION
Hepatitis A virus infection is preventable with several strategies, discussed below. Hand washing is one of the most effective strategies for reducing transmission since the virus can live on the fingers for up to four hours.
Hand hygiene — Hand washing is an essential and effective way to prevent the spread of infection. Hands should ideally be wet with water and plain or antimicrobial soap, and rubbed together for 15 to 30 seconds. Special attention should be paid to the fingernails, between the fingers, and the wrists. Hands should be rinsed thoroughly, and dried with a single use towel.
It is not clear if alcohol-based hand rubs are effective against hepatitis A virus. For this reason, food handlers, day care providers, travelers, and anyone else who is at risk of transmitting or becoming infected with HAV is advised to wash their hands with soap and water when possible. Alcohol-based hand rubs are a reasonable alternative if a sink is not available.
Hands should be cleaned after changing a diaper or touching any soiled item. They should also be washed before and after preparing food and eating, after going to the bathroom, and after handling garbage or dirty laundry.
Safe food preparation — Taking precautions when preparing foods can reduce the risk of becoming ill. The following precautions have been recommended by the Food Safety and Inspection Services (www.fsis.usda.gov) and the Centers for Disease Control and Prevention.
- Do not drink raw (unpasteurized) milk or foods that contain unpasteurized milk.
- Wash raw fruits and vegetables thoroughly before eating.
- Keep the refrigerator temperature at 40ºF (4.4ºC) or lower; the freezer at 0ºF (-17.8ºC) or lower.
- Use precooked, perishable, or ready-to-eat food as soon as possible.
- Keep raw meat, fish, and poultry separate from other food.
- Wash hands, knives, and cutting boards after handling uncooked food, including produce and raw meat, fish, or poultry.
- Thoroughly cook raw food from animal sources to a safe internal temperature: ground beef 160ºF (71ºC); chicken 170ºF (77ºC); turkey 180ºF (82ºC); pork 160ºF (71ºC).
- Cook chicken eggs thoroughly, until the yolk is firm.
- Refrigerate foods promptly. Never leave cooked foods at room temperature for more than two hours (one hour if the room temperature is above 90ºF/32ºC).
People who are preparing to travel to areas where HAV infections commonly occur should take precautions when eating and drinking to avoid becoming ill. These precautions are discussed in detail in a separate topic review. (See "Patient information: General travel advice (Beyond the Basics)", section on 'Food and water precautions'.)
Hepatitis A vaccination — Two vaccines are available to prevent infection with hepatitis A virus; the vaccines are called VAQTA and HAVRIX. Both are equally effective, and protect nearly 100 percent of people who receive two doses for a lifetime. The initial dose of either vaccine usually provides adequate short-term protection, and the subsequent doses provide long-term protection. Thus, if a person does not have time to receive both doses before traveling, it is worth administering one dose and then completing the second six to 12 months later (table 1).
The most common side effect of the hepatitis A virus vaccine is brief redness or discomfort at the injection site.
- VAQTA is given in two doses, with the second dose given six to 18 months after the first. This vaccine was temporarily recalled in the fall of 2001 because some prefilled syringes did not contain the proper amount of antigen to produce a reliable amount of antibody; this problem was subsequently corrected. People who were previously vaccinated against hepatitis A should contact their healthcare provider to determine which vaccine was given, and if revaccination is needed.
- HAVRIX is given in two doses, with the second dose given six to 12 months after the first.
If the second dose is not given within the recommended time frame, it can be given without restarting the series. A vaccination series started with one brand of vaccine may be completed with the same or other brand of hepatitis A vaccine.
Hepatitis A vaccine is recommended for all children between 12 and 23 months of age. (See "Patient information: Vaccines for infants and children age 0 to 6 years (Beyond the Basics)".)
The hepatitis A virus vaccine is recommended for all at-risk adults, including:
- Travelers to countries where hepatitis A virus is common; the vaccine can be given at any time before traveling.
- Injection and non-injection illegal drug users
- Men who have sex with men
- People with chronic liver disease
- Adults with blood clotting factor disorders
- Adults who are at risk for infection at work, including day care center staff, personnel in healthcare facilities (eg, nursing homes), and food handlers.
There is no information about the safety of the hepatitis A virus in pregnancy. However, the risk to the developing baby is likely to be low. Women who are at risk for hepatitis A and are pregnant should discuss the risks and benefits of the hepatitis A virus vaccine with their obstetrical healthcare provider.
Immune globulin — Individuals who are at risk for hepatitis A but who are allergic to components of the hepatitis A vaccine or who prefer not to receive the vaccine should consider taking a dose of immune globulin. Immune globulin is an injection that provides temporary protection against hepatitis A and reduces the risk of infection by more than 90 percent. However, the hepatitis A vaccine is preferred to immune globulin in most cases because it provides long-lasting protection and because immune globulin is not always available.
Immune globulin is given in a single injection shortly before travel. A single dose provides protection for about three months. Individuals who plan to travel for more than 5 months in areas where hepatitis A is endemic should have an additional dose of immune globulin (table 1).
Older adults and people with a weakened immune system, chronic liver disease, or other underlying medical problem who plan to travel within two weeks should be given a dose of hepatitis A vaccine in addition to a dose of immune globulin. The second dose of the HepA vaccine should be given 6 to 12 months later. Immune globulin is not required for healthy travelers who are immunized with the hepatitis A vaccine.
The timing of immune globulin relative to certain other vaccines is important. Immune globulin should be given at least two weeks after the MMR (measles, mumps, rubella) vaccine. Conversely, the MMR vaccine should be given at least three months after immune globulin. The timing of immune globulin relative to other vaccines, including the yellow fever and poliovirus vaccine, is not important.
TREATMENT AFTER EXPOSURE TO HEPATITIS A
If a person is exposed to hepatitis A and has not previously received the hepatitis A vaccine, a dose of the vaccine or immune globulin should be given as soon as possible;
- One dose of the vaccine is preferred for people aged 12 months to 40 years.
- One dose of immune globulin is preferred for people older than 40 years.
- Children who are less than 12 months and people with a weakened immune system, chronic liver disease, and those who cannot tolerate the vaccine should be given one dose of immune globulin.
- Post-exposure treatment is not necessary for people who have previously been vaccinated with two doses of the hepatitis A vaccine.
A description of the groups who require post-exposure treatment is provided in the table (table 2):
Close personal contact — Anyone who lives with, has had sexual contact with, or shared intravenous drugs with a person who is diagnosed with hepatitis A should have post-exposure treatment. The vaccine or immune globulin is suggested for anyone else who has had ongoing, frequent close personal contact (eg, a nanny) with an infected person.
Child care centers — Hepatitis A vaccine or immune globulin is recommended for unvaccinated staff and children in a day care center in some situations. A detailed explanation of the recommendation is provided in the table (table 2). The infected child or staff member should not return to day care until the fever and jaundice have resolved and the appetite has returned.
Common-source exposure — If a person who handles food in a restaurant setting becomes infected with hepatitis A, all of his or her co-workers should be treated for hepatitis A (table 2). The infected food handler should not return to work until the fever and jaundice have resolved and the appetite has returned.
It is not usually necessary to treat people who have eaten at the restaurant, unless certain criteria are met; these are described in the table (table 2). However, adults and children who regularly eat at a school or work cafeteria that employs an infected food handler may be encouraged to have post-exposure treatment; a healthcare provider should be consulted to determine if post-exposure treatment is needed in these situations.
Schools and work settings — If a single child in elementary or secondary school becomes infected with hepatitis A, it is not usually necessary to treat his or her classmates if the infection was likely acquired outside the school (table 2). Similarly, if a single adult becomes infected, his or her fellow employees do not usually need to be treated.
WHERE TO GET MORE INFORMATION
Your healthcare provider is the best source of information for questions and concerns related to your medical problem.
This article will be updated as needed on our web site (www.uptodate.com/patients). Related topics for patients, as well as selected articles written for healthcare professionals, are also available. Some of the most relevant are listed below.
Patient level information — UpToDate offers two types of patient education materials.
The Basics — The Basics patient education pieces answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials.
Patient information: Hepatitis A (The Basics)
Patient information: Latest medicines for hepatitis C (The Basics)
Patient information: Vaccines when you have hepatitis C (The Basics)
Beyond the Basics — Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are best for patients who want in-depth information and are comfortable with some medical jargon.
Patient information: Hepatitis B (Beyond the Basics)
Patient information: Hepatitis C (Beyond the Basics)
Patient information: General travel advice (Beyond the Basics)
Patient information: Vaccines for infants and children age 0 to 6 years (Beyond the Basics)
Professional level information — Professional level articles are designed to keep doctors and other health professionals up-to-date on the latest medical findings. These articles are thorough, long, and complex, and they contain multiple references to the research on which they are based. Professional level articles are best for people who are comfortable with a lot of medical terminology and who want to read the same materials their doctors are reading.
Atypical manifestations of hepatitis A virus infection
Hepatitis A virus vaccination and postexposure prophylaxis
Overview of hepatitis A virus infection in adults
The following organizations also provide reliable health information.
- Centers for Disease Control and Prevention (CDC) (available in Spanish)
Toll-free: (800) 311-3435
- National Library of Medicine
- National Institute of Diabetes and Digestive and Kidney Diseases (available in Spanish)
- American Liver Foundation