Hepatitis A is an inflammation of the liver caused by the hepatitis A virus (HAV). The virus is primarily spread when an uninfected (and unvaccinated) person ingests food or water that is contaminated with the faeces of an infected person. The disease is closely associated with unsafe water or food, inadequate sanitation, poor personal hygiene and oral-anal sex.
Unlike hepatitis B and C, hepatitis A does not cause chronic liver disease but it can cause debilitating symptoms and rarely fulminant hepatitis (acute liver failure), which is often fatal. WHO estimates that in 2016, 7134 persons died from hepatitis A worldwide (accounting for 0.5% of the mortality due to viral hepatitis).
Hepatitis A occurs sporadically and in epidemics worldwide, with a tendency for cyclic recurrences. Epidemics related to contaminated food or water can erupt explosively, such as the epidemic in Shanghai in 1988 that affected about 300 000 people (1). They can also be prolonged, affecting communities for months through person-to-person transmission. Hepatitis A viruses persist in the environment and can withstand food production processes routinely used to inactivate or control bacterial pathogens.
Geographical distribution
Geographical distribution areas can be characterized as having high, intermediate or low levels of hepatitis A virus infection. However, infection does not always mean disease because infected young children do not experience any noticeable symptoms.
Infection is common in low- and middle-income countries with poor sanitary conditions and hygienic practices, and most children (90%) have been infected with the hepatitis A virus before the age of 10 years, most often without symptoms (2). Infection rates are low in high-income countries with good sanitary and hygienic conditions. Disease may occur among adolescents and adults in high-risk groups, such as persons who inject drugs (PWID), men who have sex with men (MSM), people travelling to areas of high endemicity and in isolated populations, such as closed religious groups. In the United States of America, large outbreaks have been reported among persons experiencing homelessness. In middle-income countries and regions where sanitary conditions are variable, children often escape infection in early childhood and reach adulthood without immunity.
Transmission
The hepatitis A virus is transmitted primarily by the faecal-oral route; that is when an uninfected person ingests food or water that has been contaminated with the faeces of an infected person. In families, this may happen though dirty hands when an infected person prepares food for family members. Waterborne outbreaks, though infrequent, are usually associated with sewage-contaminated or inadequately treated water.
The virus can also be transmitted through close physical contact (such as oral-anal sex) with an infectious person, although casual contact among people does not spread the virus.
Symptoms
The incubation period of hepatitis A is usually 14–28 days.
Symptoms of hepatitis A range from mild to severe and can include fever, malaise, loss of appetite, diarrhoea, nausea, abdominal discomfort, dark-coloured urine and jaundice (a yellowing of the eyes and skin). Not everyone who is infected will have all the symptoms.
Adults have signs and symptoms of illness more often than children. The severity of disease and fatal outcomes are higher in older age groups. Infected children under 6 years of age do not usually experience noticeable symptoms, and only 10% develop jaundice. Hepatitis A sometimes relapses, meaning the person who just recovered falls sick again with another acute episode. This is normally followed by recovery.
Who is at risk?
Anyone who has not been vaccinated or previously infected can get infected with the hepatitis A virus. In areas where the virus is widespread (high endemicity), most hepatitis A infections occur during early childhood. Risk factors include:
- poor sanitation;
- lack of safe water;
- living in a household with an infected person;
- being a sexual partner of someone with acute hepatitis A infection;
- use of recreational drugs;
- sex between men; and
- travelling to areas of high endemicity without being immunized.
Diagnosis
Cases of hepatitis A are not clinically distinguishable from other types of acute viral hepatitis. Specific diagnosis is made by the detection of HAV-specific immunoglobulin G (IgM) antibodies in the blood. Additional tests include reverse transcriptase polymerase chain reaction (RT-PCR) to detect the hepatitis A virus RNA and may require specialized laboratory facilities.
Treatment
There is no specific treatment for hepatitis A. Recovery from symptoms following infection may be slow and can take several weeks or months. It is important to avoid unnecessary medications. Acetaminophen, paracetamol and medication against vomiting should be avoided.
Hospitalization is unnecessary in the absence of acute liver failure. Therapy is aimed at maintaining comfort and adequate nutritional balance, including replacement of fluids that are lost from vomiting and diarrhoea.
Prevention
Improved sanitation, food safety and immunization are the most effective ways to combat hepatitis A.
The spread of hepatitis A can be reduced by:
- adequate supplies of safe drinking water;
- proper disposal of sewage within communities; and
- personal hygiene practices such as regular handwashing before meals and after going to the bathroom.
Several injectable inactivated hepatitis A vaccines are available internationally. All provide similar protection from the virus and have comparable side effects. No vaccine is licensed for children younger than 1 year of age. In China, a live attenuated vaccine is also available.
WHO response
In May 2016, the World Health Assembly adopted the first Global health sector strategy on viral hepatitis, 2016–2021. The strategy highlighted the critical role of universal health coverage and sets targets that align with those of the Sustainable Development Goals. The strategy proposed the elimination of viral hepatitis as a public health threat by 2030 (defined as a 90% reduction in new chronic infections and a 65% reduction in mortality, compared with the 2015 baseline), and included a roadmap towards elimination by implementing key prevention, diagnosis, treatment and community interventions strategies. In May 2022 the 75th World Health Assembly noted a new set of integrated global health sector strategies on HIV, viral hepatitis and sexually transmitted infections for the period of 2022–2030. Based on these previous and now new strategies, a broad range of Member States have developed comprehensive national hepatitis programmes and elimination strategies guided by the global health sector strategy.
WHO is working in the following areas to support countries in moving towards achieving the global hepatitis goals under the Sustainable Development Agenda 2030:
- raising awareness, promoting partnerships and mobilizing resources
- formulating evidence-based policy and data for action
- increasing health equities within the hepatitis response
- preventing transmission
- scaling up screening, care and treatment services.
WHO organizes annual World Hepatitis Day campaigns (as 1 of its 9 flagship annual health campaigns) to increase awareness and understanding of viral hepatitis. For World Hepatitis Day 2022, WHO focuses on the theme “Bringing hepatitis care closer to you” and calls for simplified service delivery of viral hepatitis services, bringing care closer to communities.
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Hepatitis A is a contagious liver infection caused by the hepatitis A virus (HAV). In the USA, hepatitis A infections have declined by 90% since the hepatitis A vaccine first became available in 1995. Still, there are cases of hepatitis A reported to the San Francisco Department of Public Health every year among San Francisco residents. Hepatitis A is still common in Latin America, Africa, the Middle East, Asia, and eastern Europe.
How do People Get Hepatitis A?
Hepatitis A virus is found in the stool (feces) of people with HAV infection. It enters the body through the mouth after someone handles something contaminated with HAV, or eats or drinks something contaminated with HAV.
People usually get hepatitis A by having close contact with a person who is infected, from food or drinks prepared by someone who is infected, or by eating shellfish harvested from sewage-contaminated water. After the virus enters the body, there is an incubation period lasting 2 to 7 weeks until illness begins.
Who is at Risk for Infection?
Anyone who is not immune to hepatitis A can get hepatitis A infection. Food-borne outbreaks occur sporadically throughout the USA. Certain groups of people do have a higher risk of developing HAV infection and should be vaccinated:
- Persons experiencing homelessness
- Persons living in the same household with an infected person
- Sex partner(s) of an infected person
- Persons traveling to countries where hepatitis A is common
- Men who have sex with men
- People who use injection drugs
- Children in day care
- People who eat raw or under-cooked shellfish
How is Hepatitis A Infection Prevented?
Vaccination
- The hepatitis A vaccine offers excellent protection against HAV. The vaccine is safe and highly effective. Vaccination consists of 2 doses of vaccine (shots) spaced 6-12 months apart. Protection starts 1-2 weeks after the first dose of vaccine, and lasts for 20 years to life after 2 doses.
- The American Academy of Pediatrics recommends that all children should receive hepatitis A vaccine starting at 1 year of age (2007 AAP Statement).
- The CDC recommends hepatitis A vaccine for all persons traveling to countries where HAV is common (CDC Yellow Book). For infants that will be traveling internationally, an early dose of Hepatitis A vaccine can be given at age 6-11 months.
Natural Immunity
- People who have hepatitis A infection become immune to HAV for the rest of their lives once they recover. They cannot get hepatitis A twice.
- The blood test for immunity to hepatitis A is called the “Hepatitis A Total Antibody test.” People who have had hepatitis A and those who have received hepatitis A vaccine show positive antibodies to hepatitis A on this test for the rest of their life.
Healthy Habits
- Good personal hygiene and proper sanitation help prevent the spread of the HAV virus. Always wash your hands with soap and water after using the bathroom, changing a diaper, and before preparing, serving, or eating food.
- Alcohol-based hand sanitizers do not kill the hepatitis A virus
- People who have hepatitis A should not be preparing or serving food, or caring for the elderly or for young children, until at least 2 weeks have passed since the first sign of hepatitis A illness.
- Boiling or cooking food and drinks for at least 1 minute to 185°F (85°C) inactivates HAV. Foods and drinks heated to this temperature and for this length of time do not transmit HAV infection unless they become contaminated after heating. Travelers can lower their risk of hepatitis A (and other food-borne illnesses) in developing countries by drinking only water that has been boiled or chemically purified, by eating only foods that have been properly heated, and by avoiding fruits or vegetables that are not peeled or prepared by the traveler personally.
- Adequate chlorination of water as recommended in the United States does inactivate HAV.
After Exposure to HAV
- Hepatitis A infection can be prevented by getting vaccine or immune globulin soon after coming into contact with the virus.
- Persons who have recently been exposed to HAV should get immune globulin or vaccine as soon as possible, but not more than 2 weeks after the last exposure.
- If you have recently been exposed to hepatitis A, you should immediately contact your doctor or call the San Francisco Department of Public Health Communicable Disease Control Unit at (415) 554-2830 if you live in San Francisco. If you live outside San Francisco, call your local health department.
What are the Symptoms of Hepatitis A?
Children who become infected with hepatitis A before age 6 usually have no symptoms (70%) or mild illness, and if they do become ill, they usually get better in under 2 months. Adults and older children who become infected with hepatitis A can have no symptoms or very mild illness (30%), but most develop jaundice and other symptoms (70%). Mild illness can resolve in 1-2 weeks, but more severe illness can last for months. Common symptoms of HAV infection include:
- Jaundice
- Dark-colored urine, light-colored stools
- Fatigue
- Abdominal pain
- Loss of appetite
- Nausea
- Diarrhea
- Fever
The blood test for hepatitis A infection is called the “Hepatitis A IgM Antibody test.” People who have hepatitis A infection right now will show positive IgM antibodies on this test. While most people heal completely from hepatitis A infection, a small number, usually those with pre-existing liver disease, suffer major liver damage which can result in death (0.3-1.3%).
If you think you have hepatitis A, you should immediately contact your doctor.