African-Americans,
men, and older people were less likely to experience natural hepatitis C virus
(HCV) clearance without treatment, according to findings presented at IDWeek
2014 last week in Philadelphia, United States. Overall, out of more than 1000 people with
newly reported HCV infection, 15% spontaneously cleared the virus.
Danica
Kuncio and colleagues from the Philadelphia Department of Public Health used
clinical and risk factor data from an enhanced surveillance project to assess
differences between people with HCV who spontaneously clear their infection
and those who are chronically infected (usually considered infection lasting
longer than 6 months).
It is
generally estimated that 25 to 30% of people with acute HCV infection will spontaneously
clear the virus, but this process is not fully understood. Factors previously
associated with spontaneous resolution include various genetic factors,
non-black race, and female sex, the researchers noted as background.
In this
study, surveillance data collected between January 1, 2013 and September 30,
2014, were used to identify a random sample of people with newly reported
hepatitis C. Out of a total of 1064 people investigated, 808 received HCV RNA
tests; within the latter group, 232 (29%) were treated for hepatitis C and 576
remained untreated. People with chronic hepatitis C, as indicated by positive
HCV antibody and positive HCV RNA tests, were compared to those who
spontaneously cleared infection, as indicated by having a previous positive HCV
antibody or HCV RNA test but current negative HCV RNA test in the absence of
treatment.
The
researchers compared demographics and risk factors including injecting drugs, needle-stick injuries, receiving a blood transfusion or organ donation,
undergoing kidney dialysis, having tattoos, history of incarceration, high
number of lifetime sexual partners, being a man who has sex with men, living
outside the US for more than six months, serving in the military, having an HCV-positive mother, or having known risky contact with someone who is HCV
positive.
Results
Out of
576 untreated people with reported hepatitis C, 89 (15%) had resolved infection
with negative HCV RNA, while the remaining 487 developed chronic infection.
People
who developed chronic infection were significantly more likely to be male, more
likely to be black (versus white or Asian), and were younger than those who
spontaneously cleared HCV.
People
with chronic infection were more likely than those who cleared HCV to have risk
factors including injection drug use, sexual risk, and incarceration, but
healthcare-related risk factors did not differ.
People
with spontaneous HCV clearance and chronic infection were equally likely to be
in care and to have insurance.
"Study
findings are consistent with previous studies showing that African-Americans
and males are less likely to spontaneously clear HCV infection," the
researchers concluded. "The association between high-risk behaviours and
reduced HCV clearance may be explained by reinfection from recurrent exposure
to different viral strains among groups with elevated rates of HCV
disease," they suggested.
"By
defining the mechanisms underlying viral control, it may be possible to utilize
robust surveillance data to target individuals for treatment and/or care using
risk and demographic indicators," they added. "Ensuring that [HCV]
RNA+ individuals are linked to care for monitoring and treatment evaluation is
essential to prevent the long term effects of HCV infection, especially now
that effective medications exist."