Hepatitis B

Hepatitis B is a viral infection, which causes inflammation of the liver. The most common ways people become infected with hepatitis B are; sexual contact with an infected person, transmission from mother to baby around the time of birth and the sharing of needles or other drug-taking equipment by people who inject or use drugs. Over 90% of adults clear the hepatitis B virus within six months of infection. However, most babies who become infected develop chronic (lifelong) infection. This can cause them to develop serious liver disease, such as cirrhosis (scarring of the liver) and liver cancer as adults. Liver damage usually occurs gradually over 20-40 years in people with chronic infection. Most hepatitis B cases notified in Ireland are in people who have migrated to Ireland from countries with a higher prevalence of hepatitis B. Many were infected at birth or in early childhood and developed chronic infection.

Hepatitis B is preventable by vaccination. The hepatitis B vaccine was added to the primary immunisation schedule in Ireland in October 2008, for children born from 1^st July 2008. Vaccination is also recommended for some adults who are considered to be at higher risk of infection. For more details on vaccination, please see Immunisation Guidelines for Ireland (chapter 9)

Hepatitis B became a notifiable disease in Ireland in late 1981, but the number of cases notified annually was low until the late 1990s.

Last updated: 29 June 2026