By Seán McCárthaigh
The number of cases of people infected with hepatitis B rose by 9% last year, although the health authorities say that infection levels of the potentially fatal disease remain low here.
New figures published by the Health Protection Surveillance Centre (HPSC) show the number of notifications of the infection rose by 9% last year to 532, from 487 cases in 2016.
However, the HPSC said the prevalence of hepatitis B in the general population in Ireland remains low, at less than 1%. This is similar to most other northern European countries.
“The vast majority of hepatitis B cases notified in Ireland are chronically infected, most of whom have migrated to Ireland from hepatitis-B-endemic countries,” said the HPSC.
Most cases occurred in defined risk groups, including people with multiple sexual partners, sexual or household contact with infected persons, people who inject drugs, and people born in countries with medium or high rates of hepatitis B infection in the general population.
Despite the rise in cases of the disease last year, the HPSC said it is similar to numbers reported in 2015.
The number of notifications of hepatitis B more than halved between 2008, when figures peaked with 898 cases, and 2013, when there were 423 notifications,
“Recent trends indicate that the notification rate has stabilised and that this decline is not continuing,” said the HPSC.
The vast majority of notification of hepatitis B in the Republic related to chronic cases (long-term infection), although there were 31 acute cases (recent infections) reported in 2017, most of which were acquired via sexual intercourse. One case reported tattooing as the most likely risk factor for infection.
HPSC figures show 86% of chronic cases were born in a country with a high endemic rate of hepatitis B infection. They include parts of central and eastern Europe, Asia, and sub-Saharan Africa.
“Most of these cases were likely to have been infected outside Ireland, but the actual mode of acquisition of infection is often not known,” said the HPSC.
It said notification of hepatitis B was influenced by trends in immigration to Ireland, with the large increase in cases recorded between 1997 and 2008 linked to significant numbers of people arriving in Ireland from countries with high endemic rates of the disease.
The HPSC said people should be aware that there is a safe and effective vaccine for hepatitis B.
“Immunisation is recommended for those who change sex partner frequently, men who have sex with other men, attendees at STI clinics, and others at increased risk of infection or more severe disease,” it said.
Universal hepatitis B vaccination for infants was introduced in Ireland in 2008.
Symptoms of hepatitis B include anorexia, abdominal discomfort, nausea and vomiting, often followed by jaundice. Symptoms are milder in children, while infected infants usually show no symptoms.
The risk of developing chronic hepatitis B declines with increasing age. Approximately 90% of infants infected at birth will develop chronic hepatitis B, but the rate falls to 20-50% for those infected between one and five years of age and to less than 10% for older children and adults.
Some 15%-25% of those who develop chronic infection will die prematurely, of cirrhosis of the liver or hepatocellular carcinoma (a liver cancer).