Hepatitis A: Symptoms, Vaccine, and Treatment in Singapore
Hepatitis A is an acute liver infection caused by the hepatitis A virus (HAV). Unlike hepatitis B and C, hepatitis A is always acute and never becomes chronic. Most people recover fully within weeks to months and develop lifelong immunity, although the illness can be unpleasant and rarely causes serious complications.
Medically reviewed by Dr. Qiao Yufei, MD
This guide covers what hepatitis A is, how it spreads (fecal-oral and sexual routes), anti-HAV IgM/IgG testing, the highly effective hepatitis A vaccine, and how to protect yourself in Singapore. Hepatitis A is one of several conditions covered in our broader STDs in Singapore overview.
What is hepatitis A?
Hepatitis A is a viral infection of the liver caused by the hepatitis A virus (HAV), a small picornavirus. It causes acute inflammation of the liver, with symptoms such as jaundice, fatigue, nausea, and abdominal pain. The liver recovers fully in essentially all people who survive the initial illness.
According to the US Centers for Disease Control and Prevention (CDC), hepatitis A is highly contagious and often transmitted through contaminated food or water, particularly in regions with poor sanitation. Singapore has low endemic rates, but imported cases through travel and food are recognised, and outbreaks among men who have sex with men have been reported globally.
Hepatitis A is always acute, never chronic. This is the key clinical distinction from hepatitis B and hepatitis C, both of which can become chronic and lead to cirrhosis or liver cancer. Hepatitis A clears completely in nearly everyone, leaving lifelong immunity.
How hepatitis A differs from B and C
The three hepatitis viruses share a name but differ significantly in transmission, course, and treatment.
Always acute, fully resolves
- Transmission: fecal-oral (food, water, oral-anal sex)
- Course: acute only, weeks to months
- Chronic state: never
- Vaccine: yes, highly effective (95%+ after dose 1)
- Treatment: supportive only; recovery is the rule
- Liver cancer link: no
Can become chronic
- Transmission: bloodborne, sexual, mother-to-child
- Course: acute or chronic
- Chronic state: B in 5–10% of adults; C in 75–85% if untreated
- Vaccine: B yes; C no
- Treatment: antiviral therapy can suppress (B) or cure (C)
- Liver cancer link: yes (cirrhosis, hepatocellular carcinoma)
How hepatitis A spreads
Hepatitis A spreads through the fecal-oral route: when faeces from an infected person contaminate something another person ingests. Common transmission routes:
- Contaminated food and water: especially shellfish (oysters, clams), raw produce, ice, or food handled by an infected person who did not wash hands after using the toilet
- Travel to endemic areas: hepatitis A is widespread in parts of Asia, Africa, Central and South America, and the Middle East
- Close personal contact within households or childcare settings
- Oral-anal sexual contact ("rimming"): a recognised STI route, particularly relevant for men who have sex with men
- Sharing needles or other drug paraphernalia (rare)
Hepatitis A is NOT spread by
- Coughing, sneezing, or breathing
- Casual contact (hugs, handshakes)
- Vaginal or oral sex without faecal contact
- Blood transfusion (in countries with screened blood supply)
Signs and symptoms of hepatitis A
Symptoms of hepatitis A typically appear 2 to 6 weeks after exposure and last 2 weeks to 2 months in most people. Children under age 6 are often asymptomatic; adults usually develop noticeable symptoms.
Common symptoms
- Fatigue and general malaise
- Loss of appetite
- Nausea, sometimes vomiting
- Abdominal pain (especially right upper quadrant, where the liver is)
- Low-grade fever
- Joint pain and headache
Liver-specific signs
- Dark urine (tea or cola colour)
- Pale, clay-coloured stools
- Jaundice: yellowing of the skin and whites of the eyes
- Itching of the skin (cholestasis)
- Enlarged tender liver on examination
Most people recover fully within 2 weeks to 2 months. Fatigue can sometimes linger for several months. A small number experience a relapsing form with recurrent symptoms over 6 to 9 months. Once recovered, you have lifelong immunity.
How hepatitis A is diagnosed
Hepatitis A is diagnosed by blood test. Two antibody markers tell different stories:
Positive during active illness and for 3 to 6 months after recovery. Confirms current or recent hepatitis A. Used to diagnose acute infection.
Develops weeks after infection or vaccination and persists for life. Confirms immunity. Used to check whether you need the vaccine, or whether protection has been mounted after vaccination.
Liver function tests (ALT, AST, bilirubin) are also typically elevated during the acute phase and used to monitor recovery. At Mediway Medical Centre, both anti-HAV serology and liver function testing are available.
Hepatitis A vaccine and prevention
The hepatitis A vaccine is highly effective
The hepatitis A vaccine (Havrix, VAQTA, or combined Hep A+B as Twinrix) is one of the most effective vaccines available. Per the CDC:
- Over 95% of recipients develop protective antibodies after the first dose
- Over 99% after the second dose
- Protection lasts at least 25 years in adults and is likely lifelong
- Standard schedule: 2 doses, 6 to 12 months apart
Who should get vaccinated?
- Travellers to areas with high hepatitis A rates (parts of Asia, Africa, Central/South America, Middle East)
- Men who have sex with men (MSM)
- People with chronic liver disease (any cause)
- Household contacts and caregivers of people with hepatitis A
- People who use illicit drugs (injection or non-injection)
- Anyone seeking protection
Other preventive measures
- Wash hands thoroughly with soap and water after using the toilet, changing nappies, and before preparing food
- Drink bottled or boiled water in countries with poor sanitation
- Avoid raw or undercooked shellfish from areas with known sewage contamination
- Use barrier protection (dental dams) for oral-anal contact
Hepatitis A treatment
There is no specific antiviral treatment for hepatitis A: the immune system clears the virus on its own. Care is supportive:
- Rest and adequate hydration while symptoms are active
- Avoid alcohol completely until liver enzymes return to normal (alcohol is processed by the liver and adds stress)
- Avoid hepatotoxic medications where possible: paracetamol in moderation, avoid high doses; check with a doctor before taking other drugs metabolised by the liver
- Eat small, frequent meals if nausea is a problem
- Monitor symptoms and seek medical care if you develop confusion, severe vomiting, or worsening jaundice (rare warning signs of fulminant hepatitis)
Post-exposure prophylaxis
If you have been exposed to hepatitis A and are not vaccinated, the hepatitis A vaccine given within 2 weeks of exposure can prevent infection or significantly reduce its severity. Immune globulin is an alternative for people who cannot receive the vaccine (such as infants under 12 months or people with severe vaccine allergy).
What happens if hepatitis A is left untreated?
Most cases of hepatitis A resolve without treatment, but in a small number of cases complications can develop:
- Acute (fulminant) liver failure: rare (less than 1% of cases) but life-threatening; requires hospital care, sometimes liver transplant. More likely in older adults and people with underlying liver disease
- Cholestatic hepatitis A: prolonged jaundice and itching from impaired bile flow, lasting several months
- Relapsing hepatitis A: recurrent symptoms over 6 to 9 months before final recovery
- Prolonged fatigue: lingering tiredness for several months after the main illness resolves
Hepatitis A does not cause chronic liver disease, cirrhosis, or liver cancer: this distinguishes it from hepatitis B and C. Once recovered, you have lifelong immunity.
Frequently asked questions
01 What is hepatitis A?
Hepatitis A is a contagious liver infection caused by the hepatitis A virus (HAV). It spreads mainly through contaminated food or water and causes a short-term (acute) illness with symptoms such as fatigue, nausea, and jaundice. Unlike hepatitis B and C, hepatitis A does not become chronic, and most people recover fully and do not develop chronic hepatitis A. A safe and effective vaccine offers long-term protection.
02 What are the symptoms of hepatitis A?
Symptoms typically appear 2 to 6 weeks after exposure and may include fatigue, loss of appetite, nausea, vomiting, abdominal pain (especially upper-right side), low-grade fever, dark urine, pale stools, and jaundice (yellowing of the skin and eyes). Children under 6 are often asymptomatic, while adults usually develop noticeable symptoms. The illness lasts 2 weeks to 2 months in most people, though fatigue can linger longer.
03 How is hepatitis A transmitted?
Hepatitis A spreads through the fecal-oral route. Common ways include contaminated food and water (especially shellfish, raw produce, ice, or food handled by an infected person who did not wash hands), close personal contact within households, and oral-anal sexual contact. Travel to areas with poor sanitation is a major risk factor. Hepatitis A is not spread by coughing, sneezing, or casual contact such as hugging.
04 What is the incubation period for hepatitis A?
The incubation period is typically 15 to 50 days, with an average of about 28 days. An infected person can pass the virus to others from about 2 weeks before symptoms appear until about 1 week after jaundice develops. Because some people have mild or no symptoms, transmission can occur without anyone realising they are infected. This is why vaccination is the most reliable form of prevention.
05 How is hepatitis A diagnosed?
Hepatitis A is diagnosed by blood tests. Anti-HAV IgM indicates a current or recent infection and is positive during active illness and for 3 to 6 months after. Anti-HAV IgG usually indicates past infection or vaccination and suggests immunity. Liver function tests (ALT and AST) are usually elevated during the acute phase. Your doctor may also assess hydration and overall liver function to monitor recovery.
06 Is hepatitis A curable, and how is it treated?
Hepatitis A is self-limiting and does not require specific antiviral treatment. Most people recover fully within weeks to a few months. Treatment is supportive: rest, adequate hydration, a balanced diet, and avoiding alcohol and any medications that can stress the liver (your doctor will advise). Hospital care is rarely needed unless dehydration or severe liver inflammation occurs. Recovery from hepatitis A generally provides long-term immunity.
07 Can hepatitis A become chronic or cause complications?
Hepatitis A does not become chronic and does not lead to long-term liver disease, cirrhosis, or liver cancer. This is a key difference from hepatitis B and C. Serious complications are rare but possible: a small number of people develop prolonged or relapsing hepatitis lasting up to 6 months, and very rarely, fulminant (acute) liver failure can occur, more often in older adults or those with pre-existing liver disease. Early review by a doctor reduces risk.
08 How effective is the hepatitis A vaccine, and who should get it?
The hepatitis A vaccine is highly effective. It is usually given as two doses, with the second dose 6 to 12 months after the first for longer-term protection. Vaccination is recommended for travellers to endemic areas, men who have sex with men, household and close contacts of infected people, those with chronic liver disease, and anyone who wants protection.
09 How can I prevent hepatitis A while travelling?
The most effective step is hepatitis A vaccination, ideally completed at least 2 weeks before travel. While abroad, drink only bottled or boiled water, avoid ice made from tap water, peel fruit yourself, eat well-cooked food served hot, and avoid raw or undercooked shellfish. Wash hands with soap and water before eating and after using the toilet. These measures also reduce risk of other gastrointestinal infections.
10 Where can I get the hepatitis A vaccine or testing in Singapore?
Mediway Medical Centre offers hepatitis A vaccination, blood testing for immunity (Anti-HAV IgG), and consultation for suspected acute hepatitis at our Clarke Quay clinic. We also provide pre-travel consultations and travel vaccinations. See our vaccinations page for more information, or book a consultation through our online booking, WhatsApp, or call 6909 0190.
Related conditions and next steps
References: CDC: Hepatitis A · CDC: Hepatitis A vaccine · WHO: Hepatitis A fact sheet · HealthHub Singapore
This page is for educational purposes only and does not constitute medical advice, diagnosis, or treatment. Consult a qualified healthcare professional for diagnosis and treatment of suspected hepatitis A infection.