Pathogens and transmission
Hepatitis B is an infectious liver inflammation that is triggered by the hepatitis B virus. The highly infectious hepatitis B virus is transmitted through contact with bodily fluids (especially blood and genital secretions) of infected persons, namely by sharing injection syringes and from intercourse (genital, anal, oral), but also from small lesions of the skin or through the mucous membrane. Infected mothers can transmit the disease to their child during childbirth.
The clinical progress is very varied. The disease progresses without symptoms in about one-third of patients. In the classical form of hepatitis B, non-specific general symptoms such as loss of appetite, nausea, vomiting, stomach pains, sometimes also painful joints, fever and a skin rash may appear 45 to 180 days after infection. In most cases there is a spontaneous full recovery. However, 5%-10% of persons who become infected as adults and 90% of babies who are infected at birth develop chronic hepatitis B, which can lead to cirrhosis of the liver or to liver cancer. A chronic infection can be treated with antiretroviral drugs.
Frequency and distribution
Hepatitis B occurs worldwide, but particularly in Asian countries, the Middle East, Africa as well as parts of the Americas. In Switzerland, about 0.5% of the population are infected with the hepatitis B virus, while worldwide figures average around 3.5 %. Around 40 cases of acute hepatitis B are notified per year in Switzerland, with a downward trend. Men are much more affected by acute hepatitis B; they make up about 75% of cases. The age group 35-60 years makes up the majority of cases (roughly 55%).
Vaccination against hepatitis B is primarily recommended for infants by using a hexavalent combination vaccine at the age of 2, 4 and 12 months. Vaccination at the age between 11 and 15 years is equally recommended for adolescents not yet vaccinated against hepatitis B as well as for certain risk groups, e.g. for health care professionals and drug users.
Consistent adherence to the safer sex rules reduces the risk of becoming infected with hepatitis B. The risk of an infection can likewise be reduced by avoiding the sharing of syringes and being tattooed in countries with a high prevalence of hepatitis B.