Snorting drugs and Hepatitis C transmission- where's the link?
In some studies, hepatitis C infection has been associated with a
history of intranasal cocaine use (snorting coke).
Transmission of HCV could take place through sharing
blood-contaminated straws, notes or bullets to snort drugs.
It is unclear whether intranasal drug use is an independent risk
factor or, rather, an indication that a person practices both
injecting drug use and snorting of drugs with shared notes or straws
that could get contaminated with blood.
Research in the UK among HIV positive gay men who have recently
acquired hepatitis C has shown intranasal cocaine use to exist
alongside other potential risk factors for hepatitis C transmission,
including unprotected sex and having untreated sexually transmitted
People who use drugs may be reluctant to report their injection drug
use, so it is possible that some hepatitis C transmission may have
occurred as a result of injection drug use rather than drug snorting
but remain unreported.
A study conducted among volunteer blood donors in the United States
independently associated HCV infection with a history of intranasal
cocaine use. (The mode of transmission could be through sharing
This study showed that among volunteer blood donors, in addition to
blood transfusion and a history of injection drug use, other factors
associated with a significant risk for HCV infection were intranasal
cocaine use, sexual promiscuity, and ear piercing among men.
However, compounding this issue was that the large percentage of
people who admitted to intravenous drug use had denied such use when
questioned directly at the time of their blood donations. However,
when privately administered a separate questionnaire about
recreational drug use, 68% admitted to or recalled the use of
illegal drugs in their lifetime. (1)
Data from NHANES III (The National Health and Nutrition Examination
Surveys, conducted by the National Center for Health Statistics,
Centers for Disease Control (NCHS/CDC), designed to assess the
health and nutritional status of adults and children in the United
States through interviews and direct physical examinations)
indicated that 14% of the general population have used cocaine at
least once. (2)
Although NHANES III data also indicated that cocaine use was
associated with HCV infection, injecting-drug use histories were not
Data from another study in the United States showed young low-income
women in San Francisco and Alameda County to be infected with the
potentially deadly hepatitis C (HCV) at more than double the
national average, according to a study from the University of
California-San Francisco (UCSF). In addition to the high infection
rates among poor women ages 18 to 29, the researchers found a
possible connection to herpes and non-injection drug use, namely
cocaine snorting. (3)
The research covered 1,707 women in four counties -- San Francisco,
Alameda, San Joaquin and San Mateo. It showed that 4.3 percent of
the women studied in San Francisco and 3.8 percent of those in
Alameda County were infected with hepatitis C -- well above the
national average of 1.8 percent. Young women in two other counties
-- San Joaquin and San Mateo -- had infection rates below the
national average at 1.4 percent and zero, respectively.
In total 17.5% of the total sample reported snorting cocaine.
This study highlights the need to extend hepatitis C prevention
beyond simply blood-to-blood transmission. It seems pertinent to
address both STI prevention and treatment as well as risk reduction
when snorting drugs.
More studies are necessary to clarify the role of cocaine use in the
acquisition and transmission of HCV infection.
In a study of 276 people who had ever smoked crack or who sniffed or
snorted cocaine or heroin, published last year, 4.7 percent were
infected with HCV.
Participants who sniffed or snorted heroin and cocaine together were
most likely to be infected with HCV. The reason for the increased
risk of HCV infection among those participants may possibly be
related to the damaging effects of the drugs on the nasal mucosal
Currently, the strength of the association between intranasal
cocaine use and HCV infection means that the US Centers for Disease
Control does not support routine hepatitis testing based solely on
this risk factor. In the case of the outbreak in the UK snorting
drugs appears not to exist in isolation to other risk factors such
as unprotected sex or sex involving blood exchange.
The role of drug snorting in London hepatitis C outbreak
Researchers from the Royal Free Hospital found evidence to suggest
both sexual and intranasal transmission of HCV.
In a paper presented to the 54th Annual Meeting of the American
Association for the Study of Liver Diseases in Boston, Massachusetts
in late 2003, the authors reported that unprotected sexual
intercourse was the sole risk factor reported by all men in the
cohort, 16 subjects (70%) reported group sex and fisting, 15 (65%)
reported intranasal drug use, and four (17%) reported injected drug
The hypothesis of sexual transmission was supported by the fact that
10 (43%) had a documented STI (seven syphilis and one gonorrhoea)
including two patients with acute HIV seroconversion in the six
months prior to hepatitis C diagnosis. At the time of the
presentation last October, five isolates had been sequenced and
three appeared related by phylogenetic analysis, suggesting a common
source. Work is continuing to elucidate further possible links.