Hepatitis A, B and C

What are Hepatitis A, B and C?

Hepatitis refers to inflammation of the liver, often caused by viral infections. Among the many types, Hepatitis A, B and C are the most common and significant. While they share similarities in affecting the liver, each type differs in how it is transmitted, how long it lasts and the health risks it carries, as per the table below:

What causes Hepatitis A, B and C?

Infections occur when specific viruses infect the liver and trigger inflammation. Although Hepatitis A, B and C come from different viruses, each affects the liver cells in distinct ways.

This includes:

• Hepatitis A (HAV) – the virus enters the body through the digestive tract. Once absorbed into the bloodstream, it travels to the liver, where it infects hepatocytes (liver cells). The immune system then mounts a strong defence, causing inflammation and temporary liver injury. HAV does not usually integrate into the genetic material of liver cells, which is why it is rare to become chronic.

• Hepatitis B (HBV) – the HBV targets hepatocytes directly. Its viral DNA enters the nucleus of liver cells and can remain there, integrating into the host genome. The body’s immune response attempts to clear the virus but, in doing so, causes liver inflammation and damage. In some people, the virus persists, leading to chronic hepatitis that gradually scars the liver (fibrosis) and may progress to cirrhosis or liver cancer.

• Hepatitis C (HCV) – HCV infects hepatocytes but does not integrate its genetic material into the host DNA. Instead, it uses the liver cell’s machinery to continuously replicate. The ongoing viral replication triggers chronic inflammation, which slowly damages liver tissue. Because the immune system struggles to eliminate HCV, the infection often becomes long-term and can silently progress to cirrhosis and cancer.

What are the symptoms of Hepatitis A, B and C?

While many people may not show symptoms, especially in the early stages, hepatitis infections can cause signs that range from mild to severe. Most of the symptoms overlap, which include:

• Dark-coloured urine and pale stools
• Discomfort or pain in the upper right abdomen
• Fatigue and general weakness
• Jaundice
• Nausea and reduced appetite
• Vomiting 

Some of the additional symptoms by type are:

Hepatitis A

• Diarrhoea
• Fever

Hepatitis B

• Joint pain
• Muscle aches
• Skin rashes

Hepatitis C

• Easy bruising
• Prolonged fatigue
• Swelling in the legs

Who is at risk of developing Hepatitis A, B and C?

Hepatitis infections can affect anyone. However, certain situations or lifestyle factors can increase the likelihood of contracting each type. The risks vary depending on whether the virus is spread through contaminated food, blood contact or body fluids.

Hepatitis A

• Poor sanitation and hygiene – consuming food or water contaminated with the virus increases the chance of infection as HAV is passed through the faecal-oral route.
• Living in close quarters – crowded environments, such as dormitories or shared housing, make it easier for the virus to spread from person to person.
• Travelling to high-prevalence areas – people visiting countries with limited access to clean water and sanitation face a higher risk of exposure.

Hepatitis B

• Sharing needles or syringes – intravenous drug use can directly transmit infected blood between individuals.
• Unprotected sexual contact – HBV is present in blood, semen and vaginal fluids, making unprotected sex a major risk factor.
• Healthcare and occupational exposure – doctors, nurses and other healthcare workers are at risk if accidentally exposed to infected blood.
• From mother to child – pregnant women with Hepatitis B can pass the virus to their babies during childbirth if no preventive measures are taken.

Hepatitis C

• Sharing contaminated needles – intravenous drug use remains the most common mode of HCV transmission, as the virus spreads efficiently through blood.
• Unsafe blood transfusions (before screening) – in some countries where blood was not routinely screened in the past, recipients of transfusions may still carry HCV.
• Haemodialysis patients – long-term dialysis increases the risk of blood-borne exposure to the virus.
• Needlestick injuries in healthcare settings – healthcare professionals may be exposed if pricked by a needle used on an infected patient.

What are the complications associated with Hepatitis A, B and C?

The long-term effects differ depending on the type of infection. While all 3 variants lead to inflammation of the liver if treatment is delayed, some of the complications are:

• Hepatitis A – rarely causes long-term damage, but in severe cases may trigger acute liver failure.
• Hepatitis B – can become chronic, increasing the risk of cirrhosis (scarring of the liver), liver failure or liver cancer.
• Hepatitis C – most likely to become chronic, leading to cirrhosis, liver cancer or the need for a liver transplant.

How is Hepatitis A, B and C diagnosed in Singapore?

Accurate diagnosis is essential because the 3 types of hepatitis differ in severity, treatment approach and long-term outcomes. The diagnostic procedure typically involves:

• Medical history – our doctor will ask about recent travel, possible exposure to contaminated food or water, lifestyle habits such as alcohol use or high-risk activities and family medical history. This helps identify potential sources of infection and risk factors.
• Physical examination – a physical examination assessment may include checking for jaundice, abdominal tenderness or an enlarged liver, which are common signs of inflammation.
• Blood tests – specific blood markers help distinguish between hepatitis A, B and C:
  • Hepatitis A – detection of anti-HAV IgM antibodies indicates a recent infection, while IgG suggests past infection or immunity.
  • Hepatitis B – tests include HBsAg (hepatitis B surface antigen) to confirm infection, anti-HBs to check for immunity and HBV DNA levels to assess viral activity.
  • Hepatitis C – screening usually begins with anti-HCV antibody tests. If positive, a HCV RNA test is performed to confirm ongoing infection and measure viral load.
• Liver function tests (LFTs) – elevated enzymes (such as ALT and AST) reflect liver inflammation or injury. These results help assess the severity of infection.
• Imaging tests – ultrasound, elastography (FibroScan) or MRI can be used to evaluate liver damage, detect cirrhosis or screen for liver cancer in chronic cases.
• Liver biopsy – if the extent of damage is unclear, a biopsy may be recommended to directly assess fibrosis or cirrhosis.

How are Hepatitis A, B and C treated in Singapore?

Managing hepatitis depends on which virus is responsible, as each behaves differently in the body. Hepatitis A is short-lived and usually clears on its own, while hepatitis B may become a lifelong condition that requires careful monitoring and antiviral medication. Meanwhile, Hepatitis C, once considered difficult to treat, can now be cured in most patients thanks to modern therapies.

Hepatitis A

• Supportive care – hepatitis A does not require antiviral drugs because the infection usually clears on its own. Management focuses on rest, hydration and proper nutrition.
• Monitoring – our doctors may check liver function with blood tests until values return to normal.
• Prevention of spread – good hand hygiene and vaccination of close contacts help stop transmission.
• Long-term outlook – HAV does not cause chronic infection, so patients typically recover fully.

Hepatitis B

• Acute infection – in most adults, the immune system clears the virus naturally. Treatment usually involves monitoring and supportive care.
• Chronic infection– some people develop long-term hepatitis B, which requires ongoing management:
  • Antiviral tablets such as tenofovir or entecavir suppress viral replication and protect the liver.
  • Interferon injections may be used in select cases, though they are less common due to side effects.
• Monitoring and follow-up – patients with chronic hepatitis B need regular tests to track viral load, liver health and to screen for complications such as liver cancer.
• Advanced cases – for severe liver damage or liver failure, transplantation may be an option.

Hepatitis C

• Modern antivirals – direct-acting antivirals (DAAs) are the standard treatment in Singapore. These oral medications cure more than 95% of patients, usually within 8–12 weeks.
• Monitoring response – blood tests are performed before, during and after treatment to confirm the virus has been cleared.
• Advanced liver disease – if cirrhosis or cancer has already developed, patients may need additional treatment such as surgery, transplantation or cancer therapy.
• Long-term benefit – successful treatment prevents progression to cirrhosis and dramatically reduces the risk of liver cancer.

Summary

Living with or being at risk of hepatitis can feel overwhelming, but it is important to remember that not all forms of the condition are the same and many can be managed effectively with the right care. 

It is important to remember that early diagnosis and consistent management are the key steps to protecting your liver health and maintaining a good quality of life. Whether through simple lifestyle adjustments, antiviral medication or monitoring by a trusted doctor, taking action makes all the difference.

If you are concerned about your risk or would like to understand more about your liver health, book a consultation with our doctors at Phoenix Medical Group today.

Frequently Asked Questions