HCV and HBV Spreading More Slowly among Injection Drug Users
in San Francisco
Injection
drug users are still at very high risk of acquiring hepatitis
C virus (HCV) and hepatitis B virus (HBV);
however, needle-sharing is less common, and drug users do not become infected
as quickly as they did in the past, according to a study published on the September
2007 issue of Hepatology.
Both
HCV and HBV raise the risk of liver
cancer and other life-threatening liver disease. Past studies have shown that
most injection drug users became infected with both viruses soon after they took
up the habit. To address this danger, various groups have implemented interventions
such as needle exchange programs for at-risk populations.
Recently,
researchers sought to determine what effect such interventions may have had, by
determining the current prevalence and patterns of acquisition of HBV and HCV
among injection drug users. The investigation was led by Fan-Chen Tseng and Thomas
R. O'Brien of the National Cancer Institute, and Brian R. Edlin of the Weill Cornell
Medical College Center for the Study of Hepatitis C and former Director of the
Urban Health Study at the University of California at San Francisco.
The
investigators used data from the Urban Health Study, which recruited injection
drug users in the San Francisco Bay Area from 1986 through 2005. That study collected
demographic information along with blood samples, which were analyzed for seroprevalence
of blood-borne infections. Tseng and colleagues focused on the prevalence of HCV
and HBV antibodies among drug users who participated between 1998 and 2000, and
compared them to study participants in 1987.
Results
•
Of the 2296 injections
drug users included in the Urban Health Study between 1998 and 2000, 91% had antibodies
to HCV and 80% had antibodies to HBV.
•
However, study participants
who had recently started injecting drugs had far lower rates than the group as
a whole.
•
Only 47% of participants
who had been injecting drugs for less than 2 years were infected with HCV, compared
to 71% who had been using drugs for 6-9 years. Corresponding rates among the 1987
population were 76% and 91%.
•
For HBV, about 5%
of the more recent population had serologic evidence of vaccination against the
virus.
•
Among the remainder,
41% of those who had injected drugs for less than 2 years were infected, compared
with 57% of those who had been using drugs for 6-9 years.
•
Corresponding rates
among the 1987 population were 45% and 80%.
•
Only 34% of the participants
during1998-2000 said they had shared syringes in the past 30 days, compared to
about 59% who had done so in 1987.
Although
the population examined in this study was not a random sample, and the authors
had no way to pinpoint the reasons for the improvements over time, the observed
reductions in infection rates coincided with the implementation of street-based
outreach, HIV counseling and testing, and needle exchange programs.
The
findings suggest that there is now a longer window of opportunity for interventions
among this at-risk population. To reduce infection rates further, the authors
suggest, it is also of paramount importance to reduce the number of people who
start injection drugs and to make substance abuse treatment available to those
who wish to stop.
The
authors concluded, "It is encouraging that the frequency of HCV
and HBV appears to have decreased markedly among
new initiates to injection drug use in the San Francisco Bay Area. If the reductions
in the prevalence of these infections can be sustained, the risk of end-stage
liver disease and liver cancer should decrease in this population."
09/07/07
Reference
F-C
Tseng, T O'Brien, M Zhang, and others. Seroprevalence of Hepatitis C Virus and
Hepatitis B Virus Among San Francisco Injection Drug Users, 1998-2000. Hepatology
6(3): 666-671. September 2007.
Hepatology
is published by John Wiley & Sons on behalf of the American Association for
the Study of Liver Diseases (AASLD).
Both
HCV and HBV raise the risk of 
