In an article in Monday's Canadian Medical Association Journal, the Toronto liver specialists say people born between 1945 and 1975 should be tested because the age group is thought to account for more than 75 per cent of all cases of hepatitis C infection in Canada.
Chronic infection with the blood-borne virus is a major cause of cirrhosis of the liver and the most common reason for liver transplantation in North America.
"Baby boomers are much more likely to be infected with hepatitis C than other age groups," said co-author Dr. Jordan Feld, a liver specialist at Toronto Western Hospital.
In part, that's because the virus wasn't identified until 1989. Originally, it was called non-A, non-B hepatitis, a name that often confused people and may have left the public thinking it wasn't as dangerous as other forms of the virus.
Those now in their late 30s to late 60s could have been infected through medical procedures, such as blood transfusions, or dental work done before universal infection control measures became the norm. For instance, Canada did not begin testing blood donations for hep C until 1992.
"Most people who have the infection have no or very few symptoms, even if they've been infected for decades," said Feld. "Without symptoms, many infected people have no idea they have the disease until it's too late."
But caught early, chronic hepatitis C infection is curable in most cases, added co-author Dr. Hemant Shah, another hepatologist at the hospital.
"Hepatitis C is a silent disease until you either present with liver failure or liver cancer," said Shah.
"So what I tell my patients is it's like you're silently walking towards a cliff. And when you fall off the cliff, that's when you realize that you've been walking towards the cliff. But in a sense it's already too late."
Shah said doctors want to identify patients before they plunge into liver failure or develop a liver tumour.
"Hepatitis C is the only chronic viral infection that's curable with treatment and it will prevent them from ever falling off the cliff."
Patients can expect about a year of antiviral therapy, given both by injection and in pill form; the drugs have significant side-effects, but Shah said better-tolerated medications that would be taken for a few months are in the pharmaceutical pipeline.
Last year, the U.S. Centers for Disease Control and Prevention recommended that all Americans born from 1945 to 1965 be tested for hepatitis C.
Recently, the Canadian Liver Foundation echoed that call for a national screening program. But it stretched the birth-year period to 1975, reflecting the prevalence of hepatitis C among immigrants from regions where the disease is endemic, including northern Africa, southern Italy, Eastern Europe, and Central and Southeast Asia.
The foundation also questions the Public Health Agency of Canada's (PHAC's) estimate of 242,500 cases across the country, suggesting the figure is likely closer to 400,000.
Currently, Canada has no population-based screening program for hepatitis C, in which a simple blood test looks for antibodies to the virus. Instead, PHAC recommends doctors test patients who engage in such risky behaviours as injection drug use or certain sexual practices.
However, Shah said international studies have shown this approach is inadequate for picking up infections. "What we know is probably about 40 per cent of people who are infected have no risk factors."
As well, such screening programs rely on doctors asking about risky behaviours — which are often highly stigmatized — and patients admitting to them, he said.
"The fact that we don't talk about hepatitis C and the lack of public awareness, I think contributes to the stigma immensely," said Shah.
"(A patient) may have got hepatitis C through a blood transfusion, but when they tell someone else they have it, the immediate assumption is they must have used drugs."
And because most cases of liver failure result from cirrhosis due to alcohol abuse, patients who deny being heavy drinkers often aren't believed until blood tests come back positive for hepatitis, he said.
"I think a national screening program will help to destigmatize the condition because it's something that everyone is at risk for."
But it's critical that anyone who tests positive for hepatitis C antibodies have followup care, including a test for active infection with the virus. Antibodies show only that a person has been exposed to the virus at some point, but about 30 per cent of people are able to clear the infection.
Shah recalls a patient in his 50s who'd been told in his late 20s that he'd tested positive for hepatitis C. He broke up with the girlfriend he had intended to marry and dropped out of school, seeing no point in pursuing a career when he had a virus "that was going to kill him."
"He ended up in a bit of a spiral and he finally somehow got to me 25 years later. And I tested his viral load and it was negative."
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