2.10.0 How Many of Us Are There?
We thank Ken Thomson, BC Hepatitis C Council, for updating this section.
A 2005 corrected estimate of the number of people in the U.S. who are infected with HCV, included populations left out of the original estimate (persons who are homeless, incarcerated or hospitalized, nursing home residents, and active-duty military).
- Five million persons in the US (or more) have the HCV antibody.
- At least 4 million have the HCV RNA.
- Surveillance systems need representative samples of disenfranchised populations.
- The projected burden of liver disease in the coming decades may be underestimated.
The estimates presented here are certainly less precise than the NHANES estimate, but they are likely to be more accurate. The number of persons in the U.S. who have been infected with HCV is probably closer to 5 million than 4 million, and it may be higher still. It is important to remember that household surveys are an incomplete source of information about the prevalence of conditions affecting disenfranchised populations. To be accurate, surveillance systems need to recruit representative samples of socially marginalized populations, to estimate disease prevalence and evaluate interventions for these groups. Our current projections may underestimate the burden of liver disease in the coming decades. (Source: www.natap.org/2005/AASLD/aasld49.htm, a study presented at AASLD Nov 2005)
Experts in Long Island, N.Y. testified before two state Assembly committees that the recent increase of Hep C is linked to crystal meth combined with shared needles. The CDC predicts a 279% increase of liver damage, a 528% increase in the need for transplants, and a 223% increase in liver-disease related deaths in the US in the next 10 years. (www.hivandhepatitis.com/hep_c/news/2005/011205_a.html Jan 11, 2005)
According to the CDC, the number of new infections per year has declined from an average of 240,000 in the 1980s to about 30,000 in 2003.
There are currently 240,000 people infected with hepatitis C in Australia, with up to 16,000 new infections per year. (University of New South Wales, Sydney, Australia, 'New hope for people with hepatitis C' 24 May 2005) (The population of Australia is approximately 20 million)
251,000 Canadians are infected with hepatitis C and, because there are no symptoms, 95,000 of them don't know it. More than 5,000 Canadians -
many of whom are young people - are infected with the hepatitis C virus each year.
Look above. Are we lulling ourselves into a big problem? Australia has three times as many cases each year. Are they that different? And take
a look at the rise in liver cancer rates:
“It is suspected that there are, at present, more than 5 million people in the United States that are infected with Hepatitis C, and perhaps
as many as 200 million around the world. This makes it one of the greatest public health threats faced in this century, and perhaps one of the
greatest threats to be faced in the next century. Without rapid intervention to contain the spread of the disease, the death rate from hepatitis
C will surpass that from AIDS by the turn of the century and will only get worse.” Dr. Everett Koop, from his webpage.
Current studies indicate that most (80%) people infected with hepatitis C will develop a chronic state of infection. About 30% those with chronic infection, if untreated, will go on to develop cirrhosis of the liver. The disease appears to progress slowly; symptoms often do not appear for ten or twenty years.
After an average follow-up of 18 years, a prospective study of patients who received blood transfusions showed no difference in overall mortality between HCV-infected cases and noninfected controls. Liver-related mortality, though rare, was twice as high in the cases (3.2 percent vs. 1.5 percent). A European study showed survival among HCV patients with compensated cirrhosis was 91 percent at 5 years and 79 percent after 10 years. Among patients developing decompensated cirrhosis, however, 5-year survival was only 50 percent. - (National Institutes of Health Statement on Hepatitis C 1997)
The latest study shows that incidences of hepatocellular cancer due to hepatitis C and deaths caused by hepatitis C are almost double the rate given a few years ago. An article in the July issue of Gut reveals that ‘“of the 416 patients, 60 developed HCC with a 5-year rate of 13.4%...and 83 died (including 34 with HCC), with a 5-year death rate of 15.3%.’ According to the authors, these results contrast with previous studies, which cite 5-year mortality rates of 9%, and HCC rates of 5% or 7%.”
The overall severity of chronic hepatitis C is controversial. There is no question that HCV can lead to cirrhosis and hepatocellular carcinoma (HCC) and that end-stage chronic hepatitis C is now the leading indication for liver transplantation. At question is how frequently and how soon these serious consequences occur.
A controlled prospective study (Seeff) has shown that after 20 years of follow-up, patients with transfusion-associated hepatitis C had no increase in overall mortality and only a slight increase in liver-related mortality compared to controls who did not develop hepatitis. Another prospective study (Koretz) has shown that the probability of developing clinical cirrhosis or liver related mortality was 20% and 5%, respectively after 16 years; comparable values were 24% and 3% in the NIH series. The paradox between the relatively benign mortality figures and the observed fatal outcomes resides in the indolent nature of progressive HCV infection.
Progression is generally measured in decades and most subjects acquiring infection in mid-life or later will succumb to their underlying disease or old age before they develop end-stage chronic hepatitis C. By inference, it appears that the HCV mortality risk is approximately 4% in the first two decades and the risk will increase over time in those that do not succumb to other events. (“Natural History and Clinical Aspects of HCV Infection.” H.J. Alter. Department of Transfusion Medicine, National Institutes of Health, Bethesda, Maryland. Cancer Biotechnology Weekly, 01-29-1996, pp 20.)
Some researchers in Japan studied the progression rate of 21 Hep C patients with high ALTs who each had at least 2 biopsies a year apart. All
the patients were untreated. They found that the ALT “was an independent variable correlating with fibrosis progression.” The progression of
fibrosis was found mostly in patients who had continuously elevated ALTs even for a short period of time. In patients with an ALT over 70,
fibrosis could progress as much as one stage in 4 or 5 years (Stage 4 is cirrhosis). (J Gastroenterol. 2008;43(6):484-91.
www.ncbi.nlm.nih.gov/pubmed/18600393?ordinalpos=8&itool=EntrezSystem2.PEntrez.Pubmed.PubmedRe sultsPanel.PubmedRVDocSum Epub Jul 4. 2008)
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|2.9.10 Does HCV Increase the Likelihood of Cancer?|