High levels of hepatitis C virus (HCV) can be found in the rectal
and nasal fluids of people with high hepatitis C viral loads even when blood is
not present, Austrian researchers reported on Sunday at the 2018 AASLD Liver Meeting.
The findings reinforce the plausibility of HCV
transmission through sharing of rolled-up bank notes or other equipment for
snorting drugs.
The findings were presented by Dr David Chromy of the
Medical University of Vienna on behalf of the Vienna HIV & Liver Study
Group.
Previous
research has shown that in men who have sex with men who have hepatitis C and HIV co-infection, HCV can be detected in semen and is associated
with a higher HCV viral load in blood. A
previous study of men who have sex with men with HIV and
hepatitis C co-infection in New York found that approximately half had detectable HCV in
their rectal fluid and this was associated with having a high HCV viral load.
The study looked at levels of HCV RNA in rectal fluid and
nasal fluid in 47 adults (40 men and 7 women), 42 of them HIV positive and 23
were men who have sex with men. Participants were required to have detectable
HCV viral load (RNA). The median HCV viral load of participants was 6.03 log
IU/ml (just over 1 million IU/ml). Thirty-two per cent of participants were
acutely infected with HCV. Dr Chromy said that a majority of cases of acute
infection were detected in men who have sex with men.
Rectal fluid and nasal fluid were sampled by swabs and the
study excluded anyone with a rectal or nasal infection or other condition that
might contaminate the swab with blood. (Rectal fluid is sampled from the mucous
membrane lining the rectum.)
Seventy per cent of
participants provided at least one rectal or nasal sample that was positive for
HCV RNA. Participants were somewhat more likely to provide a positive nasal
sample (62% of all participants) than a positive rectal sample (47% of all
participants). The median viral load was significantly higher in people who
tested positive (6.28 log IU/mL vs. 4.08 log IU/mL;
p < 0.001). The median HCV RNA was higher in nasal samples (2.76 log IU/ml)
than rectal samples (1.78 log IU/ml). These levels of HCV would be
sufficient to transmit the virus.
Detection
of HCV RNA was not dependent on HIV status, on recent HCV infection or on
possible route of acquisition.
Thirty-two
study participants provided information about possible risks for HCV
acquisition or transmission during the preceding six months. Sixty-nine per cent
reported nasal drug use and just under half of these participants reported
sharing sniffing equipment. Thirty-one per cent reported injecting drug use but
sharing of injecting equipment was far less common than sharing sniffing
equipment (6%).
Two-thirds
reported receptive anal intercourse but only 6% reported frequent use of
condoms.
Dr Chromy
said that “unprotected anal intercourse and sharing of drug-sniffing tools
represent high-risk practices for HCV transmission in viremic patients,” and
that patients need to be warned of the potential risks.