An estimated 4 million Americans have Hepatitis C virus infections, although only 1 million know it. Meanwhile, 40,000 Americans acquire HIV yearly. People who contract HIV while using IV drugs, for example, are also at risk for Hepatitis C.
As many as 40 percent of individuals infected with the human immunodeficiency virus also have Hepatitis C, specialists believe. Half the patients in some US AIDS clinics are infected with both viruses.
Hepatitis C is transmitted mainly through introduction into the bloodstream, which is why IV drug users or health professionals who suffer accidental needle pricks are at high risk for contracting the virus. Tattoos and body piercing are also thought to pose a risk.
Hepatitis C is less likely to be transmitted through sexual contact than HIV or Hepatitis B, Dr. Raymond Koff, a liver specialist at MetroWest Medical Center in Framingham, said Wednesday.
Koff said that while Hepatitis C does not accelerate the course of HIV and AIDS, HIV and AIDS does speed up the liver damage caused by Hepatitis C.
Patients infected with just Hepatitis C have about 23 years, on average, before their livers fail. Patients with both viruses have about seven years before liver failure.
Contracting both diseases also complicates the already-complex treatment regimes, adding extra side effects.
Nurse Karen Daley told several hundred health care workers at the Kennedy Library conference she contracted both viruses after an accidental needle prick. Daley, who is the president of the Massachusetts Nurses Association, said the drug regime she was taking to combat HIV has affected her liver, which is already being attacked by the Hepatitis virus. The combination left her extremely ill, she said.
"The drugs have made me feel bad enough that I wanted to chuck the whole thing in July," she said.
Although the viruses are similar in the way they can be contracted, Hepatitis C can be cured in about half of patients, while there is no cure for HIV, said Dr. Douglas Dieterich of New York University Medical School.
In other findings discussed during the conference, AIDS researchers said a powerful strain HIV that had previously been found mostly in sub-Sahara Africa had been detected in the United States.
Dr. Max Essex, head of the Harvard AIDS Institute, said an unknown strain of HIV, mostly likely the strain know as Type C, had been detected in New York, Baltimore and Miami.
There are four known strains of HIV.
The C strain is more difficult to treat because it is harder to measure how much is present in blood tests, Essex said.
"It's here, but not in a big way," Essex said.
Because the C strain is thought to have infected at least half of the 33.6 million people in subSahara Africa who have HIV, developing a vaccine against the strain is critical, Essex said.