What causes
hepatitis A?
Hepatitis A is caused by a virus. It is passed on when poo from someone with the virus gets into the mouth of someone else.
The information on this page is for:
- Adults with hepatitis A or suspected Hepatitis A
- Family, friends, carers, and healthcare professionals.
On this page:
How is the hepatitis A virus passed on?
When someone has hepatitis A, the virus comes out in their poo. If this poo gets into drinking water, on to food or on to someone’s hands because of lack of good handwashing, it can be picked up and swallowed . This is the most common way for hepatitis A to spread.
After the virus is swallowed it is taken in through the stomach and small intestine. It then travels to the liver and enters the liver cells. The virus can multiply in the liver cells. It can then come out in poo and could pass on to someone else. The virus can be passed on for about a week after someone starts to get symptoms.
In rare cases, hepatitis A can be passed on by close physical contact with someone who has the virus. For example, when having sex. This is more common for men who have sex with men. And for people who share needles to inject drugs.
Sometimes there can be small outbreaks or clusters of hepatitis A cases. This happens when the virus passes on between a group of people. Usually, people who share a home. If you are in close contact with someone who has hepatitis A, you might be asked to take action to stop the spread. You can find out more about this here. [#clusters]
How common is hepatitis A?
Hepatitis A is very rare in countries like the UK where we have easy access to clean drinking water. In 2024 there were only 724 cases in England and Wales. Most UK cases of hepatitis A are picked up when someone travels to a high-risk area.
Hepatitis A is very common in places that do not have easy access to clean water. This includes parts of Africa, Asia, the Middle East and Central and South America.
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This content was last reviewed: June 2026
Our expert reviewers:
We would like to thank everyone who helped with creating and reviewing this page. Including Dr Jay Patel, Consultant hepatologist, Bedfordshire hospitals NHS trust, Kathryn Jack, Lead nurse for research and innovation, Nottingham university hospitals NHS trust, Dr. Ahmed Elsharkawy, Consultant transplant hepatologist. And all our patient reviewers.
Find out how we make our patient information.
Everyone’s experience of liver disease will be different. Always talk to your specialist medical team for personal advice.
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