TIME: Almanac 1990/1990 Time Magazine Compact Almanac, The (1991)(Time).iso/time/050189/05018900.003

Text File | 1990-09-17 | 4KB | 67 lines

MEDICINE, Page 66

Coming Soon: Safer Blood

A new test can detect an elusive and dangerous hepatitis virus


    Many people who get blood transfusions these days are
understandably nervous. Transfusions have saved countless lives,
but they have sometimes transmitted serious blood-borne diseases,
including AIDS. While public health officials point out that
careful testing has all but eradicated the AIDS virus from the
blood supply, they have not been able to claim that transfusions
are perfectly safe. Reason: about 5% of patients who receive
transfusions are exposed to a virus that can cause a potentially
deadly liver infection called non-A, non-B hepatitis.

    The mysterious malady is so named because it is not caused by
the widely recognized A and B strains of hepatitis viruses.
Symptoms include fever, nausea and fatigue and, in chronic cases,
cirrhosis of the liver. About 5% of the U.S. population harbors
non-A, non-B viruses. The majority of those who are exposed show
no symptoms, but of the patients who come down with chronic liver
disease, an estimated 10% die within five years. About 150,000 new
infections occur each year because of blood transfusions.

    This last major threat in the U.S. blood supply may soon be
greatly reduced. After six years of research, scientists at Chiron,
a genetic-engineering firm in Emeryville, Calif., have developed
a test for the presence of a non-A, non-B hepatitis virus in blood
samples. According to papers published last week in the journal
Science, trials have shown that Chiron's test is highly reliable.
It can now help eliminate the virus from the blood supply. The
inexpensive test (about $2 per blood sample) is expected to be
approved by the Food and Drug Administration this year and marketed
early in 1990 by Chiron and Ortho Diagnostics Systems, a subsidiary
of Johnson & Johnson. Said Dr. S. Gerald Sandler, medical director
for blood services of the American Red Cross: "This is a very
significant scientific achievement that virtually closes the
chapter on post-transfusion hepatitis."

    Chiron's initial breakthrough was to isolate a viral protein
from blood samples taken from patients with non-A, non-B hepatitis.
By cloning large quantities of the protein, the company was able
to develop a test to detect its presence in blood. Chiron called
the pathogen the "hepatitis-C virus." In clinical studies done at
the National Institutes of Health, the Centers for Disease Control
and laboratories in Italy and Japan, blood samples from patients
thought to have non-A, non-B hepatitis were screened using Chiron's
test. At least 80% of the samples tested positive for the
hepatitis-C virus.

    The fact that the test did not detect non-A, non-B hepatitis
100% of the time suggests that there may be still more viruses at
large that can cause hepatitis. But the A, B and C viruses seem to
cause the large majority of cases, and so researchers are confident
that they can now almost eliminate the risk of contracting
hepatitis from a blood transfusion.

    Eradicating the disease is another matter. Like the AIDS and
hepatitis-B viruses, hepatitis C is spread by sexual contact and,
among drug addicts, through contaminated needles. But Chiron's work
offers hope that the disease can be controlled. Isolating a protein
from the hepatitis-C virus has made it possible to develop a
vaccine to ward off the infection. Chiron biochemist Michael
Houghton cautions that hepatitis C could be "one of those awkward
viruses like herpes and AIDS" for which vaccines are elusive. But,
he says, the C virus resembles the one that causes German measles,
which can be prevented by one of the "best vaccines ever
developed." Chiron plans to test potential hepatitis-C vaccines in
animals later this year.