Hepatitis is a condition that causes liver inflammation, and results from an infection by the hepatitis virus of which there are a number of strains, including hepatitis A, B, C, D and E. Each strain of the virus has its own unique qualities and mode of transmission, although all of them negatively affect the liver, severely affecting its function. Should hepatitis be left untreated and become chronic, it could lead to liver cirrhosis and a heightened risk of developing liver cancer in the future.
The hepatitis A virus (HAV) can be spread through eating, drinking or coming into contact with substances contaminated with excretions or feces containing the virus. Although it is generally contracted via contact with food or drink contaminated with feces, men who have sex with men are also at greater risk than others because they may use their mouths or fingers to pleasure their partner anally as a way to prepare them for anal intercourse. Once the virus enters the body, it will incubate in the colon before gradually spreading to the liver, which will begin to inflame after approximately 1–2 weeks. This causes the person to lose their appetite, feel exhausted and experience symptoms associated with jaundice. Moreover, if the appropriate treatment is not sought during this time, it could ultimately lead to liver failure and even death.
For people who have previously been diagnosed with hepatitis A and do not wish to have a repeat infection, the hepatitis A vaccination offers almost 100% protection and provides the recipient with lifelong immunity. The vaccination can be given from the age of 1 year upwards. This is a crucial time when parents are most likely to begin taking their child outside the home or starting their education, where they could be at risk of contracting the disease via food, drinks or contact with contaminated substances. The vaccination involves two injections, given 6 months apart, although for adults with no prior immunity to hepatitis A, the 2-time vaccination can be administered 6–12 months apart, or according to the advice of their physician.
The hepatitis B virus (HBV) is particularly dangerous and can be transmitted via body fluids, including sperm or blood. If this infection is not treated appropriately, it could result in chronic liver inflammation, liver failure, liver cirrhosis and liver cancer. It can also be contracted during birth, via contact with blood, from the open wound of an infected patient, through intercourse, or by sharing sharp objects or personal objects used by an infected patient, such as needles, razors or toothbrushes.
This could quite easily be referred to as the first ever cancer vaccination due to its effectiveness in protecting against liver cancer resulting from hepatitis B infections, which accounts for up to 80% of all liver cancer cases. The hepatitis B vaccination contains surface antigen (HBsAg) proteins meaning that instead of causing a minor hepatitis B infection, the vaccine acts by stimulating the body’s existing immunity against the disease. The vaccine is a 3-time course of injections that can be administered any time after birth, with the 2nd injection due one month after the 1st, and the 3rd injection 5 months after that.
Most patients retain up to 97% immunity after receiving the full 3-time course of injections, with this immunity lasting a lifetime. However, patients should attend screening around 1–2 months after their final vaccination in order to confirm that their body has built up immunity to the disease and, in cases where this immunity is lacking, doctors may advise an additional vaccination.
Due to each hepatitis strain being unique, hepatitis vaccinations can only offer protection against the specific type for which they are designed. Anyone requiring a hepatitis vaccination should carefully identify which virus they are most at risk from in order to ensure the correct vaccination is given. Furthermore, there is now a single vaccination available that provides protection against both hepatitis A and B. If you would like more details on how to get vaccinated, please contact your regular physician or local hospital.
Faculty of Medicine Siriraj Hospital, Mahidol University , 2009