11/20/2013 11:06 EST | Updated 01/25/2014 04:01 EST

Most Canadians infected with hepatitis unaware of it

Seventy per cent of the about 138,600 Canadians infected with hepatitis C based on blood tests did not know they have the virus, Statistics Canada says. 
Wednesday's results from the Canadian Health Measures Survey come amid calls for baby boomers to be screened with a one-time test for hepatitis C infection (HCV), which liver specialists say can be eradicated if treated early and successfully. 

"Accurate infection awareness is important for health-care-seeking, receipt of treatment, vaccination uptake, and disease prevention, but more than half of respondents who tested positive for hepatitis B and hepatitis C did not know that they were infected," Michelle Rotermann of the agency's health analysis division and her co-authors concluded.

Hepatitis C is transmitted through blood, blood products, organs, tissues and cell transplants, infected needles and other sharp objects, and from mother to infant during pregnancy. Sexual transmission is less common, Statistics Canada said.

The prevalence of HCV infection from blood tests was 0.5 per cent, which represents an estimated 138,600 people. For present hepatitis B infections, the prevalence was 0.4 per cent, representing an estimated 111,800.

Among those who tested positive for HCV, 69.5 per cent said they were not aware of the infection. For those with  hepatitis B, 54.5 per cent said they didn't know they had it.  

Generally, 75 per cent to 80 per cent of people with hepatitis C develop chronic HCV infections, the authors say.

Hepatitis B and C infections are reported to provincial, territorial and national public health agencies, but accurate diagnosing and reporting is a challenge since many infections don't result in symptoms, the authors add.

They noted that many sexually transmitted and blood-borne infections are asymptomatic, which may explain why so many weren't aware of the infection.

Hepatitis B in childhood is more likely to become chronic, previous research suggests. In the early to mid-1990s, Canada rolled out universal hepatitis B vaccination programs for infants and school-aged children.

Statistics Canada said this is the first study to analyze the infections directly from a nationally representative sample of Canadian households.

The results from the 2007-2009 and 2009-2011 Canadian Health Measures Survey can be applied to the overall population aged 14 to 79.