There are more than three million carriers of hepatitis B worldwide and the virus is second only to tobacco smoking as a cause of cancer mortality, a conference heard yesterday.
Dr Brian O'Herlihy, director of public health with the Eastern Health Board, said that on a global basis hepatitis B was a very serious disease, causing a significant number of deaths and liver cancers. "As a carcinogen it is second only to tobacco," he said. About 1 per cent of those infected with hepatitis B go on to develop serious complications, Dr O'Herlihy said. About 10 per cent become "chronic carriers", however, getting over the infection but remaining infectious and able to pass it on to others for the rest of their lives through blood or sexual contact.
According to official figures it is estimated that more than one-third of the world's population has been infected with the hepatitis B virus. There are about 350 million chronic carriers, about 5 per cent of the world's population.
The World Health Organisation (WHO) estimates that hepatitis B infection results in more than one million deaths a year worldwide. Often the disease is asymptomatic and long-term complications only occur after many years.
Dr O'Herlihy said that while the prevalence in Ireland and other north European countries was low, the WHO recommended the universal vaccination of children. "There is no evidence that the prevalence of the disease is on the increase in Ireland and it would not seem to be a matter of urgency to rush into a vaccination programme," he said. He said there was a policy here at present for risk groups to be vaccinated.
However, Dr Deirdre Kelly, director of the liver unit at the Birmingham Children's Hospital, said that selective vaccinations of high-risk groups had failed as a strategy.
"High-risk people may not be recognised in time, they are often reluctant to be identified and there is no effective means of delivering vaccines to these groups. Focusing particularly on high-risk groups also means not detecting infection in seemingly low-risk persons," Dr Kelly said.
Dr O'Herlihy said that Irish and international research showed there was a much higher prevalence of hepatitis B infection in institutions for the mentally handicapped, probably because of behavioural problems such as excessive scratching.