Matilda Wellness

Hepatitis A Alert: The "Silent" Outbreak & Why Screening Is Your First Defence

Written by Dr. Ivan CHOI Man Kei | 25 Mar, 2026

Any good doctor knows that while medicine is powerful, prevention is always better than cure. Hepatitis A is making a resurgence in Hong Kong. While the virus is often associated with contaminated shellfish or travel to developing regions, recent investigation by the Centre for Health Protection (CHP) highlights a shift in transmission patterns. A cluster of genetically linked cases recorded between late 2025 and early 2026 indicates that person-to-person transmission—specifically among men who have sex with men (MSM)—is driving the current spread. 

Whether you are part of a high-risk community, a frequent traveller, or simply a lover of raw seafood, understanding your immunity status is the most effective way to protect your health.

The "Silent" Risk: How It Spreads

Hepatitis A is a highly contagious liver infection caused by the hepatitis A virus (HAV). Unlike Hepatitis B or C, it does not usually cause chronic liver disease, but it can be debilitating and, in rare cases, lead to acute liver failure.

Transmission Routes

According to the CHP, the current outbreak suggests a strong link to sexual transmission (specifically oral-anal contact). However, the classic environmental risks remain significant for the general population:

  • Contaminated Food & Water: Consuming raw or undercooked shellfish (oysters, clams), contaminated water, or food handled by an infected person.
  • Close Contact: Living with or caring for someone who is infected.

Symptoms: The Waiting Game

The virus has a long incubation period—usually 14 to 28 days, but sometimes up to 50 days. An infected individual can spread the virus for weeks before feeling ill.

Early signs include:

  • Fever
  • Fatigue
  • Loss of appetite
  • Nausea and abdominal pain

Watch out for the "Red Flags" (liver impact):

  • Jaundice: Yellowing of the skin or whites of the eyes
  • Dark urine (tea-coloured) or pale stools.
  • Intense itching

Note: If symptoms of jaundice or severe abdominal pain appear, immediate medical attention is required. Gastroenterologists are best equipped to manage these liver complications.

The Strategy: Screen Before You Vaccinate

With global supply chains for vaccines fluctuating, the most efficient clinical approach is to verify immunity before seeking vaccination.

Many adults in Hong Kong already possess natural immunity due to:

  1. Past Exposure: A previous, perhaps mild or asymptomatic, infection.
  2. Childhood Vaccination: Vaccinations received years ago that are still effective.

The Anti-HAV IgG Screen 

A simple blood test of Anti-HAV IgG can confirm your status immediately.

  • Fast: Requires only a quick blood draw during a standard General Practitioner (GP) consultation.
  • Definitive:
    • Positive (+): Antibodies are present. You are immune and do not need the vaccine.
    • Negative (-): You are vulnerable. Your GP can then discuss the option of two-dose vaccination series, which provides lifelong immunity.

Who Should Get Screened?

While Hepatitis A can affect anyone, specific groups currently face a heightened risk of infection or severe complications. Understanding your category helps determine the urgency of your screening.

1. Men who have sex with men (MSM) 

The Centre for Health Protection has identified this demographic as the primary group affected by the current outbreak. The virus is present in faeces and can easily spread through sexual activities involving oral-anal contact or close physical intimacy.

  • Why Screen? Since the virus can be transmitted even before symptoms appear, knowing your antibody status is crucial for protecting both yourself and your partners.
  • The Holistic Approach: A GP consultation for Hepatitis A screening is an excellent opportunity to conduct a comprehensive sexual health check-up (STI screening) in a private, confidential setting.

2. Enthusiasts of Raw Seafood and "Foodies"

Hepatitis A is notoriously resilient and can survive in filter-feeding shellfish—such as oysters, clams, and mussels—even when harvested from waters that appear clean.

  • The Risk: Shellfish concentrate the virus in their tissues. Consuming them raw or undercooked poses a significant transmission risk.
  • Why Screen? If dining out and enjoying raw delicacies is part of your lifestyle, confirming your immunity provides peace of mind without requiring you to alter your dietary habits unnecessarily.

3. Frequent Travelers

Hong Kong is a travel hub, and many popular destinations in Southeast Asia and beyond are considered endemic zones for Hepatitis A due to varying sanitation standards.

  • The Risk: Exposure can occur through tap water, ice cubes, or uncooked fruits and vegetables washed in local water.
  • Why Screen? Travelers often assume they were vaccinated as children but may not have completed the full course. An antibody test confirms whether you are protected before your next trip.

4. Individuals with Chronic Liver Conditions

This is the most medically critical group. Patients with pre-existing liver issues—such as Chronic Hepatitis B, Hepatitis C, or Non-Alcoholic Fatty Liver Disease (NAFLD)—are at risk of "superinfection."

  • The Danger: Contracting Hepatitis A on top of an existing liver condition significantly increases the risk of severe complications, including fulminant hepatitis (acute liver failure).
  • Why Screen? For this group, prevention is not just about avoiding illness; it is about preventing a life-threatening medical emergency. Screening is strongly advised to ensure immunity is present.

Take Action

Protecting yourself and the community starts with awareness. Whether you choose public or private healthcare, knowing your antibody status is the most responsible step you can take during this outbreak.

Public Healthcare Options 

The Centre for Health Protection (CHP) is actively managing the outbreak and providing vaccinations for high-risk groups (specifically MSM) at designated social hygiene clinics and integrated treatment centres. We encourage eligible individuals to check the latest government announcements for location details and eligibility criteria.

Private Medical Care 

For those who prefer a specific appointment time, a higher degree of privacy, or do not qualify for the government’s targeted programme (such as travelers or food enthusiasts), private clinics offer a convenient alternative.

Post-Exposure Protection

If you have been in close contact with a confirmed case, immediate action is required. Receiving a vaccine or immunoglobulin within 14 days of exposure can effectively interrupt the infection before it starts. This is a critical window for preventing the spread. Confirmed cases are reported to the CHP to support public health surveillance and outbreak control.

Next Steps

  • Consult a doctor: Discuss your lifestyle risks with a General Practitioner.
  • Screen first: Request the Anti-HAV IgG Screening to confirm if you are already immune.
  • Plan ahead: If your result is negative (non-immune), your doctor can advise on vaccination availability or appropriate preventive measures.

 

Articles on this website are informative only and not intended to be a substitute for professional medical advice, diagnosis or treatment. They should not be relied upon for specific medical advice.

Source of reference:

  1. Centre for Health Protection (CHP). Hepatitis A - Health Topics https://www.chp.gov.hk/en/healthtopics/content/24/24.html

  2. Centre for Health Protection (CHP). Press Releases & Statistics https://www.chp.gov.hk/en/media/116/index.html

  3. World Health Organization (WHO). Hepatitis A: Key Facts, Transmission, and Prevention https://www.who.int/news-room/fact-sheets/detail/hepatitis-a

  4. Centers for Disease Control and Prevention (CDC). Hepatitis A Questions and Answers for Health Professionals https://www.cdc.gov/hepatitis/hav/havfaq.htm 
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