Understanding hepatitis (A, B and C)

What hepatitis is and why the liver matters

The liver processes almost everything absorbed from the gut, breaks down waste and old blood cells, makes proteins that help blood clot, and stores vitamins and energy. When a virus infects the liver, the immune system's response causes inflammation, which can make the liver work less well. Short-lived (acute) hepatitis may cause a flu-like illness, tummy discomfort and jaundice, then settle. Long-lasting (chronic) hepatitis can quietly damage the liver over many years, leading to scarring called cirrhosis and, in some people, liver cancer. Because chronic hepatitis often causes few symptoms early on, many people do not know they have it, which is why testing matters so much, even for those who feel completely well.

Hepatitis A: caught from food and water

Hepatitis A spreads mainly through food or water contaminated with tiny traces of infected faeces, and through close contact, including in some travel destinations with poorer sanitation. It causes an acute illness with tiredness, sickness, tummy pain and jaundice, which can be unpleasant but almost always clears on its own without lasting liver damage. It does not become a long-term infection. There is no specific medicine; treatment is rest, fluids and time, while avoiding alcohol so the liver can recover. The good news is that hepatitis A is largely preventable: a safe and effective vaccine is recommended for travellers to higher-risk countries and for certain at-risk groups, and careful hand and food hygiene reduces the chance of catching or spreading it.

Hepatitis B: blood and bodily fluids

Hepatitis B spreads through blood and bodily fluids, for example from mother to baby at birth, through unprotected sex, and through sharing needles. In adults it often causes an acute illness that the immune system clears, but in some people, and in most infected babies, it becomes a chronic infection that can slowly scar the liver over decades. There is an excellent, safe vaccine, now given routinely to all babies in the UK as part of the childhood schedule, and offered to people at higher risk. Chronic hepatitis B cannot always be cured, but effective long-term antiviral medicines can keep the virus under control, protect the liver and greatly reduce the risk of cirrhosis and liver cancer, alongside regular monitoring.

Hepatitis C: often silent, now curable

Hepatitis C spreads mainly through blood-to-blood contact, most commonly through sharing needles or equipment for injecting drugs, and in the past through unscreened blood transfusions. It frequently causes no symptoms for years, quietly becoming a chronic infection that can scar the liver, which is why so many cases were historically found late. There is no vaccine for hepatitis C. The remarkable change of the last decade is treatment: modern direct-acting antiviral tablets, taken for a matter of weeks, now cure the great majority of people with very few side effects. The NHS has run major programmes to find and treat people with hepatitis C, and testing is easy, so anyone who may have been exposed is encouraged to come forward.

Testing, prevention and living well

Diagnosis is made with simple blood tests that detect the virus or the body's response to it, and further tests can check how the liver is coping. Testing is recommended for anyone with possible exposure, symptoms or risk factors, and it is confidential. Prevention combines vaccines for hepatitis A and B, safer sex, never sharing needles or personal items that might carry blood such as razors, and good food and hand hygiene. For people living with hepatitis, avoiding alcohol, keeping to a healthy weight and staying up to date with monitoring all help protect the liver. With today's vaccines and medicines, hepatitis is far more preventable and treatable than in the past, and early diagnosis makes a real difference to long-term health.