US military veterans
of the baby-boom generation form a population at higher-than-average risk of
hepatitis C. Hepatitis C prevalence is higher in adults born between 1945 and
1965 due to higher levels of injecting drug use and greater lifetime risk of
exposure to blood transfusions containing hepatitis C compared to those born
after 1965.
Veterans may be at
especially high risk of hepatitis C infection due to high levels of
injecting drug use among the population that served during the Vietnam War era
and blood exposure in battle or medical settings. Tattooing and transmission
through use of airguns for vaccination during military service are difficult to
quantify as sources of infection, but many veterans – particularly those who
did not see active service in Vietnam – believe these routes explain their
infection with hepatitis C.
Furthermore, the
Veteran’s Health Administration (VA) medical system may have an especially high
prevalence of hepatitis C among its patient population because it has tended to
retain in care veterans who have sought treatment for problems with substance use through
the VA system.
Lisa Backus of the
Veteran Affairs Office of Public Health presented an analysis of the proportion
of veterans receiving care through VA system who might remain undiagnosed.
The VA examined its
database of 5.5 million veterans in care to determine what proportion of
patients who attended a medical appointment in 2012 had been tested for
hepatitis C between 1999 and 2012. The VA began risk-based screening for
hepatitis C following a CDC recommendation in 1998.
The researchers found
that 54% of all veterans had been screened for HCV at least once (41.5% of
those born before 1945, 64.2% of those born between 1945 and 1965 and 58% of
those born after 1965).
Of those screened, 95%
received confirmatory HCV RNA screening, yielding a chronic infection rate of
1.7% for those born before 1945, 9.9% in those born between 1945 and 1965, and
1.1% for those born after 1965.
Hepatitis C prevalence
among newly screened veterans declined with each year – suggesting that those
at greatest risk would have been tested earlier – from 33% in 1999 to 5.7% in
2012.
Based on these rates
of infection, the researchers estimated that if the remaining 905,000 veterans
in the 1945 to 1965 birth cohort underwent hepatitis C testing, an additional
51,000 veterans with hepatitis C would be identified.
Two other studies
presented at the conference showed higher than expected prevalence of hepatitis
C infection among emergency room attendees, among pregnant women and among
adults in primary care, and demonstrated that relying on self-disclosed risk
factors alone to prompt hepatitis C testing would result in the majority of
infections going undiagnosed.