1. What is Hepatitis A?

Hepatitis A (colloquially: infectious jaundice / "dirty hands disease") is an infectious liver disease caused by the HAV virus. Infection most often occurs via the fecal-oral route: through contaminated food or water or "hand-to-mouth" contact after contact with the excretions of an infected person. Infection is also possible during sexual contacts, especially with oral-anal practices; infection through blood is rare.

The source (reservoir) of the pathogen is humans – a sick person or an asymptomatic carrier.

The incubation period averages 28 days (usually 15–50 days).

Who is most at risk?

travelers to countries with higher endemicity,
people having risky sexual contacts (including MSM),
people using drugs,
people in difficult sanitary conditions or exposed professionally (e.g., working with food/sewage),
people with chronic liver disease and/or reduced immunity – in them the risk of severe course is greater.

2. Symptoms of Hepatitis A

In older children and adults, symptoms often appear suddenly.

Most common are:

fever, weakness, muscle pain,
lack of appetite, nausea/vomiting, abdominal pain,
dark urine, pale stool,
jaundice (yellowing of the skin and whites of the eyes).

The course can range from mild to severe. In children <6 years old, about 70% of infections may be asymptomatic, and jaundice occurs less frequently than in adults.

Complications: acute liver failure rarely occurs, but the risk increases with age and with liver diseases.

Urgent medical consultation is needed when the following occur, among others: increasing drowsiness/confusion, severe vomiting and dehydration, bleeding, very severe abdominal pain, rapidly increasing jaundice, or when a person with liver disease / reduced immunity is sick.

3. Where does Hepatitis A occur?

HAV occurs all over the world, but the highest risk concerns areas with worse hygienic and sanitary conditions. Endemicity is high in, among others, parts of African, Asian, and Central and South American countries.

Important practical rule for travelers: CDC recommends vaccination for all susceptible people traveling to countries with high or intermediate endemicity, and some experts consider vaccinating travelers "just in case" also regardless of the destination (due to e.g., food risk).

This is particularly important for:

"exotic", touring, backpacking trips,
longer stays and visits to family (VFR),
work/volunteering in the field or outside large cities.

4. How to protect yourself against Hepatitis A?

A. General prevention

Wash your hands after using the toilet, before eating and preparing meals (this is the most important rule).
When traveling: drink safe water (bottled/treated), avoid ice of unknown origin, eat well-cooked dishes, watch out for raw fruits/vegetables (wash/peel).
Reduce sexual risk: barrier protection, avoiding practices increasing the risk of contact with feces.

B. Vaccination

Type of vaccine: vaccines with inactivated (killed) HAV virus are most often used.

For whom recommended?

especially for travelers to countries with high/intermediate endemicity,
for people from increased risk groups (e.g., MSM, drug use, occupational exposure, homelessness),
for people with chronic liver disease and some people with immunosuppression (after doctor's assessment).

Vaccination schedule (most frequent):

2 doses at an interval of 6–12 months (ensures the best, long-term protection).
A combined Hepatitis A + Hepatitis B vaccine is also available (e.g., 0–1–6 months) and an accelerated schedule 0–7–21/30 days + dose after 12 months (depending on indications).

Booster doses: after completing the full cycle, they are usually not recommended.

How long does immunity last? After a full cycle, antibodies persist for at least 20 years (and studies suggest very long protection in many people).

Important note (after exposure): if exposure occurred, vaccination (and in selected groups also immunoglobulin) can act as post-exposure prophylaxis if administered as soon as possible, preferably within 2 weeks.

5. Summary

Hepatitis A spreads easily (most often through dirty hands, water, and food) and in adults can be severe, with a risk of liver complications. Vaccination is the most effective method of protection – especially for travelers, people with liver diseases, and those who have an increased risk of contact with HAV. If you are planning a trip, it is best to get vaccinated 2–4 weeks before travel so that the body has time to develop protection (and ultimately finish the full schedule for long-term immunity).