Plans for once-off screening of up to one-third of the population for hepatitis C are unlikely to proceed after a study found prevalence of the virus was much lower than previously estimated.
Between 3,500 and 5,000 people in Ireland are infected long-term with hepatitis C, according to the study – as little as 10 per cent of previous estimates made over a decade ago.
With just one person in 1,000 infected, it would not be cost-effective to screen the most at-risk cohorts in the population, born between 1965 and 1985, for the virus, the study by a team from the HSE’s National Hepatitis C Treatment Programme says.
However, a much higher prevalence was identified in two urban parts of Dublin – an estimated 0.39 per cent of men in the 1965-85 cohort in the southwest and northeast of the capital are infected with hepatitis C compared with a national figure of 0.11 per cent. Targeted screening is suggested in these areas.
Hepatitis C is a viral infection causing inflammation of the liver. It is spread through contact with the blood of an infected person, most often now through the sharing of needles in drug abuse. One-quarter of infected people will clear the virus within a year but the remainder develop long-term infection that can lead to cirrhosis of the liver and cancer.
New drugs are available that can cure 95 per cent of cases but critics of official policy claim not enough is being done to bring these treatments to drug-users and other marginalised groups who may not interact regularly with hospitals and other health services.
More than 14,000 blood samples were tested for the study, published in the Irish Journal of Medical Science. Just 17 were positive for hepatitis C, of which 12 had the hepatitis C antigen that triggers an immune response from the body.
The study found only 17 per cent of patients had hepatitis C antibodies, indicative of previous infection, whereas previous studies assumed 75 per cent of infections become chronic.
The World Health Organisation has set a target of 2030 for the elimination of hepatitis C; by then, 90 per cent of patients should be diagnosed and 80 per cent treated.
In 2009, it was estimated that 20,000-50,000 people in Ireland had hepatitis C; a second estimate in 2016 put the figure at 20,000 and estimated that 70 per cent of patients were born between 1965 and 1985.
In 2017, the Irish national hepatitis C screening guidelines recommended a screening programme for this cohort. A health technology assessment concluded it would be cost effective on the basis of the numbers estimated. The cost of carrying out screening was estimated at €44-65 million.
Due to uncertainty over the number of patients affected, the Health Information and Quality Authority recommended further research before screening went ahead.
With the current study finding prevalence is “much lower” than previously estimated, a planned pilot screening programme is unlikely to go ahead.
The fact that only 17 per cent of hepatitis C antibody-positive patients had hepatitis C antigen suggests that spontaneous clearance rates are high, or there has been a significant uptake of curative antiviral treatment or a combination of both,” according to the study. “These results also suggest that Ireland is on track to achieve the WHO elimination targets for hepatitis C.”
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