June 1999
WASHINGTON, D.C. - More people are infected with hepatitis C virus (HCV) in this country than there are people with HIV, Leslye D. Johnson, PhD, explained here recently at a press conference sponsored by the National Foundation for Infectious Diseases.
This means health care workers (HCWs) must consider this virus in patients. Because this is a bloodborne pathogen, universal precautions are important to protect HCWs as there is no vaccine and treatment is limited, she added. "The primary message is that the standard precautions that all physicians should be practicing should be made more prominent in their minds with the knowledge that they could end up with a chronic liver disease," she said.
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About 4 million people in the United States are persistently infected with HCV. In some inner cities, 20% of people coming into emergency departments are HCV positive. The virus infects and damages the liver, causing about 8,000 to 10,000 deaths each year and the number of deaths is expected to increase threefold over then next 10 to 15 years, added Johnson, chief of the Enteric and Hepatitis Diseases Branch, Division of Microbiology and Infectious Diseases at the National Institute of Allergy and Infectious Diseases.
"HCV is also the major reason that people receive liver transplants, roughly half of all the liver transplants done in this country are done because of hepatitis C," said Johnson. About 50% of chronic carriers do not realize they are infected even during the acute phase because most of the disease is asymptomatic. "The symptoms may mimic the flu, so you can have a little nausea, you can be fatigued, but you might not think off the top of your head that you have hepatitis C," she said.
"People are living, walking and breathing fine all around you, and they have hepatitis C. There are others who obviously are on the other end of that spectrum and are severely debilitated. It is a disease that goes over a spectrum during its own course so that the symptoms become more severe the longer you have the infection," she explained.
In the late 1980s, about 200,000 new cases occurred each year, most through transfusion. Now, the number is running at about 35,000 new cases a year. The decrease is probably due to HCV screening of the nation's blood supply.
"If you got it 10 years ago, which is when most people who are going to show up on doctors' doors got their infection, transfusion was the major source of that infection as was illegal drug use particularly injection drug use [IDU]," Johnson said. "It was transmitted from blood and blood products, so people who were hemophiliacs, not only got HIV, but HCV and hepatitis B virus [HBV]. Hemodialysis is a risk factor."
There is a small risk of maternal-fetal transmission, she explained.
"It is sexually transmitted, but poorly, unlike hepatitis B," she said. People who have had multiple sex partners or used injection drugs are most at risk. Johnson said a group of IDUs who are not always considered are athletes who inject anabolic steroids. "Any use of unsterile needles is a risk factor."
Cocaine use can be a risk because people who snort cocaine often share straws. If there is break in the membrane of the nose, the virus can be transmitted. The risk is small, she said, but data suggests it is present.
"The disease is spread around the world at about these same rates, and there is estimated to be about 175 million chronic carriers around the world," Johnson said. In the United States, there are more chronic carriers of HCV than of HBV.
Hepatitis C is a 50 nm RNA virus in the Flaviviridae family. The incubation period is from six to 12 weeks. "That means for HCV like HIV, there is a window period when you are infectious, and there is no way to detect it," she explained. Diagnostics test for antibody not the virus itself. It is probably a good idea to retest patients after 12 weeks if the first test is negative.
Liver biopsy can be used to diagnose late-stage disease and to assess liver damage.
Some experts think 15% of infected individuals rid themselves of the virus, the other 85% are chronic carriers. Twenty percent of chronic carriers will develop cirrhosis; 20% of those with cirrhosis will develop liver cancer. No effective treatment for liver cancer exists.
Sequela tend to be worse for men. Alcohol is a significant risk factor for enhancing disease progression, so patients should be advised to give up drinking. Some experts say one or two drinks are okay. "If I was someone who was infected, I think I would stop all together," she said.
The other hepatitis viruses tend to exacerbate disease, therefore, physicians should recommend hepatitis A and B vaccination to protect from those diseases.
"Even though there is no vaccine to prevent this disease, even though the therapies are not wonderful at this point, the therapies are better," she said.
Four therapies are licensed to treat this infectious disease. There are three types of interferon monotherapies: a-2b (Intron, Schering); a-2a (Roferon, Roche Laboratories) and Consensus Infergen (Angen). A new combination product combines interferon a-2b with ribavirin (Rebetron, Schering). However, the response rate is low with all of them. Genotypes differ from country to country. Genotype 1 is the dominant type in this country and responds the least to these therapies. For those who are responsive, total elimination of the virus is possible.
Therapies have to be given for months at a cost of about $18,000. Total health care costs for treatment are about $2 million dollars.
Blood banks are currently doing a lookback investigation to identify those who may have received infected blood products before blood was tested for HCV. The lookback encompasses the years 1988 to 1992. Blood banks are identifying lot numbers for blood donors who were later identified as HCV positive. Information will be given to transfusion services, which will notify the recipient that he or she should be tested. Johnson said it was unlikely that a large percentage of people will be identified this way, but it will be beneficial for those who are found.
Testing can be difficult for foreign-born patients because the genotype varies around the world; the U.S. tests do not identify the genotype from other countries, she added.
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