What Is Hepatitis A?
A highly contagious viral liver infection spread through contaminated food and water, preventable by vaccination.
Pathogen: Hepatitis A virus (HAV, Hepatovirus genus, Picornaviridae family)
Type: Virus
Transmission
Faecal-oral route through ingestion of contaminated food or water, or direct contact with an infected person. Shellfish harvested from contaminated water, raw produce washed in contaminated water, and food prepared by infected handlers are common sources.
Vector: No arthropod vector. Faecal-oral transmission via contaminated food, water, or direct contact.
Symptoms
Abrupt onset of fever, malaise, nausea, anorexia, abdominal discomfort, followed by dark urine, pale stools, and jaundice (yellowing of skin and eyes). Severity increases with age — children under 6 are often asymptomatic; adults usually have symptomatic illness.
Incubation period: 14 – 50 days
Average 28-30 days. Infected individuals are most infectious 2 weeks before to 1 week after the onset of jaundice.
Timeline: Symptoms develop 2-7 weeks after exposure. Illness typically lasts 1-2 weeks but can persist for months. Prolonged or relapsing hepatitis occurs in 10-15% of cases. Full recovery is the rule.
Case fatality rate: Overall <0.5%. Higher in adults over 50 (up to 1.8%) and those with pre-existing liver disease. Fulminant hepatic failure is rare but can occur.
Diagnosis & Treatment
Diagnosis: Anti-HAV IgM antibody in serum (positive at symptom onset, detectable for 3-6 months). Elevated liver enzymes (ALT, AST). Anti-HAV IgG indicates past infection or vaccination and confers lifelong immunity.
Treatment: No specific antiviral treatment. Supportive care including rest, adequate nutrition, and avoidance of alcohol and hepatotoxic medications. Hospitalisation may be needed for severe dehydration or liver failure. Recovery is usually complete.
Prevention
- Hepatitis A vaccination (highly effective, long-lasting protection)
- Drink only bottled, boiled, or treated water
- Avoid raw or undercooked shellfish
- Eat only freshly cooked food served hot
- Peel fruit yourself; avoid pre-prepared salads
- Wash hands thoroughly with soap before eating and after using the toilet
💉 Vaccine Available
A vaccine is available for Hepatitis A. View the Hepatitis A vaccine guide for details on schedule, cost, and availability in Australia.
Post-Exposure
Post-exposure prophylaxis with hepatitis A vaccine (within 14 days of exposure) or immunoglobulin (for those over 50, immunocompromised, or with chronic liver disease) can prevent or attenuate infection.
Long-Term Effects
Hepatitis A does not cause chronic infection. Full recovery with lifelong immunity is the norm. Rarely, fulminant hepatic failure can occur, particularly in older adults or those with pre-existing liver disease. Relapsing hepatitis can prolong illness for several months.
📋 Hepatitis A is a nationally notifiable disease in Australia. Around 100-200 cases are notified annually. The vaccine is funded under the NIP for Aboriginal and Torres Strait Islander children in high-risk areas.
Frequently Asked Questions
Do I need a hepatitis A vaccine for travel?
Yes. Hepatitis A vaccination is recommended for virtually all travellers to developing countries in Asia, Africa, Central and South America, and the Pacific Islands. It is one of the most commonly recommended travel vaccines in Australia. A single dose provides protection within 2-4 weeks, and a booster at 6-12 months gives long-lasting immunity (likely lifelong).
How many doses of hepatitis A vaccine do I need?
Two doses are recommended: the first dose at least 2 weeks before travel, and a second (booster) dose 6-12 months later for long-term protection. Even a single dose provides excellent short-to-medium term protection and can be given up to the day of departure. The combination hepatitis A/B vaccine (Twinrix) requires 3 doses over 6 months, or an accelerated schedule.
Can you get hepatitis A in Bali?
Yes. Indonesia, including Bali, is considered high-risk for hepatitis A. The virus is transmitted through contaminated food and water. Even upmarket restaurants and hotels can be sources if food handlers are infected. Vaccination before travel to Bali is strongly recommended.
What foods should I avoid to prevent hepatitis A?
Avoid raw or undercooked shellfish, raw salads and vegetables washed in local water, unpeeled fruit, ice made from local water, and food from street vendors with questionable hygiene. The travel health maxim 'boil it, cook it, peel it, or forget it' applies. Even vaccinated travellers should exercise basic food hygiene.
How long does hepatitis A protection last after vaccination?
A single dose provides protection for at least 1 year, possibly up to 10 years. The full two-dose course (with a booster at 6-12 months) is believed to provide protection for at least 25 years and likely lifelong. Booster doses beyond the two-dose course are not currently recommended.
Is hepatitis A the same as hepatitis B?
No. Hepatitis A is transmitted through contaminated food and water (faecal-oral) and does not cause chronic infection. Hepatitis B is transmitted through blood and body fluids (sexual contact, needlestick injuries, contaminated medical equipment) and can cause chronic liver disease, cirrhosis, and liver cancer. Different vaccines are available for each, or a combined vaccine (Twinrix) can protect against both.
Can you still get hepatitis A if vaccinated?
The hepatitis A vaccine is highly effective — approximately 95-100% protective after a single dose. Vaccine failure is extremely rare. However, no vaccine is 100% effective, and it takes 2-4 weeks after the first dose for full protection to develop. Maintaining safe food and water practices is still recommended.
I'm travelling in 3 days — is it too late for the hepatitis A vaccine?
No. While the vaccine ideally should be given 2-4 weeks before travel, a dose given even on the day of departure provides some protection. The Australian Immunisation Handbook supports vaccination up to the day of travel. Some protection develops within days, and the vaccine is effective enough that even last-minute vaccination is worthwhile.
Sources & References
Last updated: April 2026