Hepatitis A and the Vaccine


Hepatitis A, or Hep A, as its name suggests, is a contagious disease caused by Hep A virus.

Hepatitis is the medical term referring to an infection in the liver. In the general population, it is usually caused by hepatitis viruses A, B, C, D, and E. The virus spreads by contact with infected people, their fluids and waste.  The World Health Organization (WHO) estimates that there are 1.5 million cases of Hepatitis A virus (HAV) infections every year worldwide, with around 5000 to 10000 fatalities. As of today, Asia and Africa are both considered endemic zones of Hep A. Since 1990s, two types of vaccine – the inactivated and the live-attenuated vaccine have been made available and have drastically reduced the number of infections worldwide. 

What are the symptoms of hepatitis A?

The liver is one of the most important organs in our body that is responsible for multiple key functions. These include:

  • Production of blood clotting factors
  • Production of bile
  • Blood cell recycling
  • Provide immunity
  • Protein metabolism
  • Fat metabolism
  • Sugar metabolism

People with liver infection usually manifest in a similar manner, and symptoms include: 

  • Yellowing of the skin or eye white (Jaundice)
  • Generalised itchiness 
  • Dark urine
  • Light-coloured stool
  • Abdominal pain or discomfort
  • Diarrhoea
  • Nausea and vomiting
  • Loss of appetite or refusal to eat or drink in toddlers
  • Fever
  • Fatigue

Sadly, there is no available treatment for hep A infection. Usually, the body’s immunity fights the virus off and heals within 6 weeks. Resting, hydration and avoidance of alcohol could be suggested to minimise the risk of developing acute liver failure.

When should I get the vaccine? 

As per the US Center for Disease Control (CDC)’s advice, children need 2 doses of the hepatitis A vaccine.

  • First dose: 12 through 23 months of age
  • Second dose: at least 6 months after the first dose

Usually, the vaccination works in 95% of the cases and can provide a minimum of 20 years of immunity. In adulthood, people can choose to test for immunity with a simple blood test. Another booster dose could be given if there is no antibody detected. 

What are the different types of hep A vaccines?

There are more than a dozen different brands of hep A vaccine available worldwide. However, the vaccines can be broadly divided into two main groups – live-attenuated and inactivated. 

As their name suggests, live-attenuated vaccines are made from live but attenuated viruses. The virus’s ability to cause disease has been suppressed but is still strong enough to induce an immune response in our body. Inactivated vaccines are made from killed viruses. The molecular pieces of the virus can be recognized by our immunity and form immunological memory. In some jurisdictions, people are only required to have one dose of hep A vaccine if they choose the live-attenuated type, due to the stronger immunological effect. However, live-attenuated vaccines must be used with caution in the immunodeficient population, as the vaccine itself can cause liver infection due to weakened immunity. 

Meanwhile, some products combine hep A and hep B vaccines into one dose. Consult your local medical practitioner for more information. 

What are the side effects of hep A vaccination?

Unlike its COVID counterpart with so many side effects, the hep A vaccine has been generally considered safe. Minor side effects can happen but usually, they are not big causes of concern. These include:

  • Injection site reaction: swelling, tenderness, redness, warmth, or hard lump
  • Low-grade fever
  • General ill feeling
  • Nausea
  • Loss of appetite
  • Headache

If you have children, it is important to keep an eye on them after they receive any type of vaccine injections. Always go to your doctor if you are unsure or worried about their symptoms. 


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