LAS VEGAS — Amid the alphabet soup of hepatitis virus types, the one that should most concern physicians these days is hepatitis C.
“This is going to be the big virus in the next 20 years in the U.S.,” Dr. Marsha H. Kay predicted at a meeting sponsored by the American Academy of Pediatrics.
Hepatitis C virus already infects 1.6% of the general U.S. population—4 million people—but “the vast majority of people who are infected do not know it,” said Dr. Kay, a pediatric gastroenterologist and director of pediatric endoscopy at the Cleveland Clinic.
Known to be at risk are infants born to mothers with hepatitis C; young adult survivors of leukemia, childhood malignancies, and childhood cardiac surgery; hemophilia patients; dialysis patients; intravenous drug users; sexual partners of a person with hepatitis C; recipients of blood transfusions prior to 1989; first responders; and health care workers.
Alarmingly, though, 32% of the current cases involve no known risk factor. “We don't know exactly how this virus is transmitted,”sDr. Kay said. There is no way to prevent hepatitis C, and there is no vaccine.
Among those infected, 80%-85% will develop chronic hepatitis, and of those, half will develop cirrhosis, putting them at highly elevated risk for hepatocellular carcinoma. Hepatitis C is already the leading cause of liver transplantation in the nation.
All things considered, the perfect storm of hepatitis C constitutes “a really terrible outcome compared to hepatitis B infection,” she said,.
Among children, the leading cause of hepatitis C transmission is perinatal exposure, with transmission risk correlated to the mother's viral load at delivery.
Unfortunately, drugs used to treat acute hepatitis C are teratogenic and cannot be used during pregnancy. Hepatitis C acquired via perinatal transmission has an increased likelihood to be chronic. Anti-HCV testing is ideally performed between 15 and 18 months of age. Although HCV RNA testing may be positive at 2 months and 6 months, the results may be a response to the mother's sera at that time.
Other patients who should be considered at risk in a primary care practice include young people who overcame serious illnesses early in life and those who received blood products before 1989.
Individuals who received Gammagard (immune globulin) during 1993 and 1994 may also be at risk.
Health care providers, especially those who work in emergency departments, surgery, or procedurally related specialties, have an estimated 1% prevalence rate that is rising, she said.
“I have to say, the majority of the kids I see in my practice with hepatitis C are the children, typically, of a nurse—a health care provider who likely got it occupationally,” she noted.
New data suggest that prompt treatment with interferon and ribavirin may produce a sustained virologic response in up to 80% of patients with acute hepatitis C. “If you're sure of [acute infection], you want to treat them early,” she said.
Antibody testing has been available for nearly 20 years, but the antibody just signals exposure to the virus, not immunity. Current detection modes include PCR (polymerase chain reaction), which can sometimes detect virus within 1-2 weeks of exposure but may be intermittently negative even in positive patients; ELISA (enzyme-linked immunosorbent assay)-IgG, which is highly sensitive and specific late in the course of the disease but may be inaccurate early; and RIBA (recombinant immunoblot assay)-IgG, a confirmatory test.
Clinically, liver function tests may generate variable results throughout the course of the disease.
Dr. Kay disclosed no relevant conflicts of interest regarding her talk.
Health care providers have an estimated 1% prevalence rate that is rising.
Source DR. KAY