As discussed last week, hepatitis A is an acute and usually self-limiting disease of the liver caused by the hepatitis A virus. This virus is transmitted from person to person, primarily by the feco-oral route i.e. personal contact with an infected person and ingestion of contaminated food and water.
As we mentioned in the article, the incidence of hepatitis A is related to the socioeconomic development of the country in question. Studies have shown widely different rates of infection in different countries, ranging from 15 per cent to 100 per cent in some countries in the African continent and the Far East. In countries such as Malta, hepatitis A usually occurs as single cases in persons in high-risk groups, or alternatively, as outbreaks involving a relatively small number of persons, therefore not sufficient to be termed an epidemic. In poorer countries with inadequate sanitation and with high incidence of hepatitis A, infection occurs in childhood and is usually without any symptoms. On the other hand, in countries such as Malta, adults are likelier to become infected and these are usually symptomatic.
A vaccine for hepatitis A is available and this is administered as two doses four to eight months apart, for individuals over one year. The vaccine locally available is inactivated, that is, it does not contain any live virus and it is very effective with no serious side effects. The vaccine is not recommended for use in children under the age of one and is not routinely given by the Maltese NHS.
Hepatitis B virus is transmitted through unscreened blood products and through intimate (e.g. sexual) contact, leading to acute or chronic disease, the potential for acute or chronic liver failure, and the possibility of a permanent carrier state. Children are more likely to suffer chronic infection than adults and treatment is very limited and expensive.
Hepatitis B vaccines are prepared using recombinant DNA technology, i.e. the vaccine does not contain, and has never actually been in contact with, the virus itself. This vaccine is also very effective with no serious side effects. Since hepatitis B infection may cause chronic liver disease with eventual cancer of the liver, vaccination with this vaccine is also an anti-cancer vaccination. The three-dose schedule for this vaccine is at zero, one to two months and four to six months. It may be given shortly after birth prior to hospital discharge in babies at risk (e.g. parent/s who are actively infected with hepatitis B or chronic carriers or drung abusers). For individuals such as for health care workers, a single booster is advocated after five years. This vaccine is routinely given to all children by the Maltese NHS.
A combination vaccine containing inactivated hepatitis A and recombinant hepatitis B vaccine is available for children aged one or older in several countries, and is given as a three-dose series, using a zero, one, six-month schedule.
A combination vaccine containing inactivated hepatitis A and recombinant hepatitis B vaccines is available for individuals aged one year or older, and this is given as a three-dose course in the same way as the hepatitis B vaccine.
There is no vaccination for hepatitis C at the time of writing.