| |
Household Contact
Case-control studies
also have reported an association between non-sexual household contact
and acquiring hepatitis C. The presumed mechanism of transmission is
direct or inapparent percutaneous or permucosal exposure to infectious
blood or body fluids containing blood. In a recent investigation in the
United States, an HCV-infected mother transmitted HCV to her hemophilic
child during performance of home infusion therapy, presumably when she
had an unintentional needle stick, and subsequently used the
contaminated needle in the child.
Although prevalence
of HCV infection among nonsexual household contacts of persons with
chronic HCV infection in the United States is unknown, HCV transmission
to such contacts is probably uncommon. In studies from other countries
of nonsexual household contacts of patients with chronic hepatitis C,
average anti- HCV prevalence was 4%. Although infected contacts in these
studies reported no other commonly recognized risk factors for hepatitis
C, most of these studies were done in countries where exposures commonly
experienced in the past from contaminated equipment used in traditional
and nontraditional medical procedures might have contributed to
clustering of HCV infections in families.
Transmission of Hepatitis C among Family Members in Egypt
A study published in
the current issue of Hepatology (September 2005) examines the
incidence and risk factors associated with Hepatitis C virus (HCV)
infection in rural Egypt..
The prevalence of antibodies to Hepatitis C Virus (HCV) in Egypt is
among the highest in the world. From the 1950s until 1982 hundreds of
thousands were infected during mass campaigns to control schistosomiasis
(a parasitic disease) using mass therapy with intravenous antimony
compounds, but little is known about current risk factors and rates of
transmission. Studies of high risk populations, such as intravenous drug
users, shed little light on
HCV
transmission in Egypt where this high risk behavior is
rare.
In a study led by G. Thomas Strickland, M.D. of the Department of
Epidemiology and Preventive Medicine at the University of Maryland
School of Medicine in Baltimore, MD, Egyptian and American researchers
surveyed rates of HCV infection in two rural communities having a
prevalence of antibody to HCV of 24 and 9 percent.
A total of 10,112 HCV negative individuals were identified during an
annual survey in 1997, with follow-up performed on an average of 1.6
years later in 6,738 subjects. Of these, 33 developed HCV antibodies, an
incidence of 3.1/1000 person-years (PY), and 6.8/1000 PY in the 28
subjects in the village having the 24 percent prevalence of HCV. None of
the 33 individuals was diagnosed with viral hepatitis or reported
symptoms of acute hepatitis.
An analysis of risk
factors showed the strongest predictor of infection with HCV was having
an anti-HCV positive family member
[emphasis added-Ed]
Among those that did, incidence was 5.8/1000 PY, compared to
1.0/1000 PY; 27/33 incident cases had an anti-HCV positive family
member. Parenteral exposures increased the risk of HCV, but were not
statistically significant; 67 percent of seroconverters were less than
20 years old, and the highest incidence rate (14.1/1000 PY) was in
children under 10 living in households with an anti-HCV positive parent
in the village with the high prevalence of HCV antibodies. The infection
rate was also increased (13.1/1000 PY) in men married to an HCV positive
woman.
"We believe HCV exposures in rural Egyptian communities are usually less
intense than those in individuals infected by contaminated blood, either
from transfusion of blood or a blood product, or from abuse of
intravenous drugs," the authors state.
Although not
statistically proven to be a risk in this study, they cite frequent
injections, usually given at home for health purposes with syringes and
needles sometimes used for more than one person, as the most common
parenteral exposure route. The strong relationship between the risk of
infection in children and the presence of HCV antibodies in their
parents suggests that transmission of HCV is occurring between family
members, possibly by exposure to infectious blood or saliva, or by
sharing needles.
In the past, mass
treatment campaigns for schistosomiasis involving multiple injections
may have caused numerous HCV infections in families, but this would not
account for current infection rates, other than placing younger members
of families living with those who contracted HCV in this way at higher
risk.
The authors conclude: "It is exceedingly important to learn the
mechanisms by which HCV transmission is occurring between family members
so that preventive measures can be initiated, particularly in children
having HCV-infected parents."
08/24/05
Reference
G T
Strickland and others. Intrafamilial Transmission of Hepatitis C in
Egypt. Hepatology 42(3): 683-87. September 2005. Article is
available via
Wiley InterScience
.
Can Hepatitis C Be Transmitted by Sharing
Toothbrushes?
Guidelines for
the prevention of
hepatitis C virus (HCV) transmission often include a warning against
sharing toothbrushes, razors, nail care equipment, and other personal
items that potentially may come into contact with blood. While studies
definitively show that HCV can be transmitted by sharing needles and
other equipment used for drug injection, the risk of sharing
personal care articles is less clear.
German
researchers performed a study to examine whether toothbrushes of
HCV positive people
are likely to be contaminated with the virus. The study included 30
participants with chronic hepatitis C. For each, 2 mL of saliva,
collected before and after tooth brushing, plus toothbrush rinse water
were tested for
HCV RNA.
Results
 Saliva collected before
tooth brushing was positive for HCV RNA in 9 patients (30%).
Saliva collected after
brushing the teeth had detectable HCV in 11 patients (36.7%).
12 toothbrush rinse
water specimens (40%) tested positive for HCV RNA.
In 6 of these 12
patients, the "native" saliva (taken from the mouth) had been
negative for HCV RNA.
Patients with
detectable HCV RNA in their toothbrush rinse water showed no
significant differences from those with negative rinse water with
respect to clinical, biochemical, and virological parameters.
Conclusion
In conclusion,
the authors wrote, "Our study demonstrates a contamination with HCV RNA
of a considerable portion of toothbrushes used by hepatitis C patients,
suggesting at least a theoretical risk of infection by sharing these
objects."
They added that
these results support "strengthening the recommendations to [ensure] a
clear separation of these personal care objects between patients and
their household members."
09/01/06
Reference
G Lock, M Dirscherl, F Obermeier, and others. Hepatitis C
contamination of toothbrushes: myth or reality? Journal of Viral
Hepatitis 13(9): 571-573. September 2006.
Tattoo and HCV
NEW YORK Anyone with a tattoo should be tested for hepatitis C,
according to researchers who conducted a recent study in New York.
The researchers studied 3,871 people, according to a report on medical-news.net,
and found that patients with HCV were more likely to have had one or
more tattoos. This was true and even after the data were adjusted for
age, gender and ethnicity. When patients with the most common risk
factors for HCV, injection drug use and blood transfusion prior to 1992,
were removed, patients with HCV were about three times more likely to
have had tattoos.
Nov. 1, 2007
Needle Stick Exposure and Hepatitis C
By Nancy Reau, MD and Donald M. Jensen,
MD
Hepatitis C virus (HCV) is a hepatitis
virus transmitted through blood-to-blood exposure. Hepatitis C is commonly
acquired through blood product transfusions (primarily before 1992), needle
sharing (including acupuncture), tattooing, body-piercing, and even through
sharing personal hygiene items. In as many as 10% of individuals
transmission route cannot be explained.
What is my risk of acquiring hepatitis
C from a needlestick?
Unlike hepatitis B virus, hepatitis C is not efficiently transmitted from a
needlestick. The average rate of seroconversion (changing from hepatitis C
antibody negative to hepatitis C antibody positive) after an occupational
exposure to HCV positive blood is about 1.8%, but has ranged as high as
7-10% in some studies. This risk is highest with hollow-bore needles.
What can be done to prevent the
transmission of hepatitis C?
There is currently no vaccine or immunoglobulin (IG) to protect against HCV
transmission. Several studies evaluating the response to passive
immunoglobulin found that high anti-HCV titer IG did not prevent
transmission. This makes sense given that the rapid mutation rate of HCV
allows the virus to escape from any protective antibody that may form during
infection. Postexposure treatment with interferon, with or without ribavirin,
is also confusing and controversial. At present, however, there is no
recommendation for the use of antiviral therapy following needlestick
exposure to an HCV-positive source.
What should I do if Im exposed to HCV
positive blood?
Currently, the best recommendation is to carefully monitor for laboratory
abnormalities, signs and symptoms of acute hepatitis C infection. Acute
hepatitis C is a difficult disease to study. This is due to the declining
incidence of acute hepatitis C and the fact that most patients are not
initially symptomatic. Given these limitations, a non-controlled study
evaluating the response to a 24-week course of interferon alfa (Jaeckel et
al.,: Treatment of Acute Hepatitis C with Interferon Alfa-2b. NEJM
2001;345:1452-1457) found that 98 percent of treated patients exhibited a
sustained biochemical and virologic response 24 weeks after treatment of
acute hepatitis C. These are exciting results, especially given that
previous studies suggested that only 15-30% of individuals with acute
infection recover without treatment.
Should we treat everyone with acute
hepatitis C or exposure to hepatitis C? Before recommending any treatment,
we should be sure that it is the best thing for the patient. Interferon is
expensive and has many side effects, some of which could be
life-threatening. The study was not controlled (i.e., there was not a group
with acute hepatitis C that did not receive treatment). We know that 15-30%
of patients exposed to hepatitis C will recover without any treatment. In
addition, the patients in the study were symptomatic and often had jaundice.
Previous investigations suggest that progression to chronic hepatitis C is
much lower in young patients with jaundice, making it more likely that these
individuals could have spontaneous clearance. The individuals in the study
were not treated immediately after exposure, but rather months after they
had symptoms. This would suggest that therapy could be delayed without
adverse affects, allowing patients to spontaneously recover before
prescribing an expensive and difficult to tolerate medication. But the
number one reason that interferon therapy is not standard in acute infection
is that we need more data to ensure that this is the most beneficial
treatment to offer. Currently, the US public health service guidelines for
management of HCV exposures include:
- Baseline testing for anti-HCV and ALT activity
- Follow-up testing at 4-6 months for anti-HCV and ALT
activity or HCV RNA at 4-6 weeks
- Exposed individuals should not donate blood, plasma,
organs, tissue, or semen
- Exposed person does not need to modify sexual practices
or refrain from pregnancy or discontinue breast feeding
- When HCV infection is confirmed early, the person should
be referred for medical management to a specialist in this area
- IG and anti-viral agents are not recommended
The 2002 NIH Consensus conference recommended that patients
with acute hepatitis C were potential candidates for interferon therapy, but
realized many questions remained unanswered, particularly: which patients
with acute HCV should be treated, and when is the ideal time to start
therapy?
Copyright February 2003 Hepatitis C
Support Project - All Rights Reserved. Permission to reprint is granted and
encouraged with credit to the Hepatitis C Support Project.
Back to Medical Writers' Circle
http://www.hcvadvocate.org/hcsp/articles/Jensen.html
Also see :
Infection
Control:
Hepatitis C
Issues and Answers for Health Care Workers
http://www.hivdent.org/infctl/hepatiti.htm
Reducing Risk Of Vertical
Hepatitis C Transmission
A DGReview of :"Mother-to-child transmission of hepatitis C virus: evidence
for preventable peripartum transmission"
Lancet
09/15/2000
By Mark Greener
Vertical transmission of hepatitis C virus (HCV) appears to occur
predominantly around delivery, a new study suggests.
The study also suggested that elective caesarean section before membrane
rupture may virtually eliminate the risk of vertical transmission.
The authors note that until this study, few papers examined the timing of
vertical HCV transmission. Moreover, no intervention was known to reduce
transmission rates.
The new study enrolled 441 mother-child pairs from the UK and Ireland and
used Polymerase Chain Reaction (PCR) assays to measure levels of HCV RNA
(viral load).
Half the uninfected children became HCV-antibody negative after eight
months. This increased to 95 per cent after 13 months. The authors estimated
PCR's sensitivity as "only" 22 per cent during the first month. However,
PCR's sensitivity rose to 97 per cent after the first month. The assay's
sensitivity was not age-related.
Overall, the vertical transmission rate was 6.7 per cent. However, the
vertical transmission rate was 3.8 times higher in the 22 women who were
co-infected with HIV compared to those infected with HCV alone, after the
authors adjusted for confounding factors.
Only 59 women breastfed. However, breastfeeding did not appear to affect the
likelihood of transmission.
The study revealed that delivery by elective caesarean section before
membrane rupture may virtually eliminate the risk of vertical transmission
compared to delivery either vaginally or by emergency caesarean section.
After adjusting for other factors, the authors estimated the average odds
ratio for the risk of vertical transmission among babies delivered by
elective caesarean section as zero.
In conclusion, the authors highlighted two findings suggesting that vertical
HCV transmission occurs mainly around delivery. PCR's low sensitivity soon
after birth and the reduced risk of transmission following elective
caesarean section.
The authors suggest reconsidering the value of antenatal HCV testing if
further investigations confirm that elective caesarean section reduces the
likelihood of vertical transmission.
Hepatitis C in pregnancy
Risk Factors for Mother-to-child Transmission of
Hepatitis C Virus
By Liz Highleyman
Hepatitis C virus (HCV)
infection in children is mainly acquired via
mother-to-child (perinatal) transmission. In a study published in
the August 20,2007 issue of AIDS, French researchers sought to
identify risk factors for mother-to-child HCV transmission, in
particular those associated with maternal virological characteristics or
mode of delivery.
The investigators
included 214 HCV positive women and their newborn infants seen at 6
hospitals in southern France between October 1998 and September 2002.
About one-quarter (55%) of the women were
HIV-HCV coinfected. The authors collected data on maternal
characteristics, circumstances of delivery, and laboratory data for the
mothers and children. All babies were followed for 1 year, and those
with detectable plasma HCV RNA for 2 years.
Results
In total, 12
infants had detectable HCV RNA at 1 year of age, yielding an overall
mother-to-child transmission rate of 5.6%.
3 of these
children became HCV RNA negative between 12 and 18 months of age and
achieved normal alanine aminotransferase (ALT) levels.
137 women (69%)
had detectable plasma HCV RNA, including all those whose children
were infected.
6 children were
born to HIV-HCV coinfected women with detectable HCV RNA, for a
transmission rate of 13.6%.
6 were born to
HCV monoinfected women with detectable HCV RNA, for a transmission
rate of 6.5%.
The risk of
mother-to-child HCV transmission was 3 times higher for HCV-HIV
coinfected women compared to those with HCV alone (P = 0.05).
When maternal
HCV RNA levels were below 6 log IU/ml, the rate of transmission was
significantly higher in HIV-HCV coinfected women (odds ratio 8.3; P
= 0.01.
This association
with HIV status did not exist, however, for women with detectable
HCV RNA levels of 6 log IU/ml or higher.
The rate of HCV
transmission did not differ significantly between children born by
vaginal delivery or Caesarean section after membrane rupture and
those born by elective Caesarean section, independent of HIV status.
Conclusion
These findings
confirm results of past studies showing that HIV-HCV coinfected women
are more likely to transmit HCV to their babies than those with HCV
alone. The study also confirmed that HCV viral load plays an important
role in mother-to-child transmission/
Department of
Public Health, France; CHU Nice, France; CHU Toulouse, France; CHU
Montpellier, France; CHG Antibes, France; Virology Laboratory, France;
INSERM U379, France.
08/21/07
Reference
E Marine-Barjoan, A Berrebi, V Giordanengo, and others (for
the ALHICE study group). HCV/HIV co-infection, HCV viral load and mode
of delivery: risk factors for mother-to-child transmission of hepatitis
C virus? AIDS 21(13): 1811-1815. August 20, 2007.
http://www.hivandhepatitis.com/hep_c/news/2007/082107_a.html
Discordant Mother-to-Child Transmission of HCV in Twin Pregnancies
May 2007
Perinatal
The average rate of HCV
infection among infants born to HCV-positive, HIV negative women is 5%-6%
(range: 0%-25%), based on detection of anti-HCV and HCV RNA, respectively.
The average infection rate for infants born to women co-infected with HCV
and HIV is higher - 14% (range: 5%-36%) and 17%, based on detection of anti-HCV
and HCV RNA, respectively. The only factor consistently found to be
associated with transmission has been the presence of HCV RNA in the mother
at the time of birth. Although two studies of infants born to HCV-positive,
HIV-negative women reported an association with titer of HCV RNA, each study
reported a different level of HCV RNA related to transmission. Studies of
HCV/HIV-coinfected women more consistently have indicated an association
between virus titer and the transmission of HCV.
The
only consistent factor found to be associated with
HCV transmission during birth is the presence of HCV
in the mother at the time of birth
Data regarding the
relationship between delivery mode and HCV transmission are limited and
presently indicate no difference in infection rates between infants
delivered vaginally compared with cesarean-delivered infants. The
transmission of HCV infection through breast milk has not been documented.
In the studies that have evaluated breastfeeding in infants born to HCV-infected
women, the average rate of infection was 4% in both breastfed and bottle-fed
infants.
Diagnostic criteria for
perinatal HCV infection have not been established. Various anti-HCV patterns
have been observed in both infected and uninfected infants of anti-HCV-positive
mothers. Passively acquired maternal antibody might persist for some months,
but probably not for >12 months. HCV RNA can be detected as early as 1 to 2
months.
Pregnancy and Breast feeding
Should pregnant women be routinely tested
for anti-HCV?
No. Pregnant women have no greater risk of being infected with HCV
then non-pregnant women. If pregnant women have risk factors for
hepatitis C, they should be tested for anti-HCV.
What is the risk that HCV infected women
will spread HCV to their newborn infants?
About 5 out of every 100 infants born to HCV infected women become
infected. This occurs at the time of birth, and there is no
treatment that can prevent this from happening. Most infants
infected with HCV at the time of birth have no symptoms and do well
during childhood. More studies are needed to find out if these
children will have problems from the infection as they grow older.
There are no licensed treatments or guidelines for the treatment of
infants or children infected with HCV. Children with elevated ALT
(liver enzyme) levels should be referred for evaluation to a
specialist familiar with the management of children with HCV-related
disease.
Should a woman with hepatitis C be advised
against breast-feeding?
No. There is no evidence that breast-feeding spreads HCV. HCV-positive
mothers should consider abstaining from breast-feeding if their
nipples are cracked or bleeding.
When should babies born to mothers with
hepatitis C be tested to see if they were infected at birth?
Children should not be tested for anti-HCV before 18 months of age
as anti-HCV from the mother might last until this age. If diagnosis
is desired prior to 18 months of age, testing for HCV RNA could be
performed at or after an infant's first well-child visit at age 1-2
months. HCV RNA testing should then be repeated at a subsequent
visit independent of the initial HCV RNA test result.
Prevention of
Spread of HCV
Miriam J. Alter, Ph.D.
Historically, the
most reliable data on risk factors associated with acquiring hepatitis C
virus (HCV) infection have been obtained from cohort (prospective) studies
that determined the risk of developing acute infection after a specific
exposure and case-control (retrospective) studies that determined if a
history of exposure before onset of disease was associated with newly
acquired (acute) hepatitis C. Risk factors identified by these studies in
the United States included injecting drug use, blood transfusion and solid
organ transplants from infected donors, occupational exposure to blood
(primarily contaminated needle sticks), birth to an infected mother, sex
with an infected partner, or multiple heterosexual partners.
The major limitation
of such studies is that they are unlikely to identify associations with
exposures that result only rarely in infections. For example, results of
case-control studies have indicated no association between acquiring
hepatitis C and exposures resulting from medical, surgical, or dental
procedures. However, outbreaks of HCV infection have been associated with
contaminated equipment in hemodialysis settings and unsafe injection
practices in both inpatient and outpatient settings. Most of these outbreaks
have involved patient-to-patient transmission. Only two instances of
transmission have been reported from HCV-infected health care workers to
patients in the United States. Neither of these was associated with the
performance of exposure-prone invasive procedures, but rather with
contamination of patients narcotics used for self-injection.
The contribution of
these various risk factors to the overall burden of HCV infections is
influenced both by their efficiency in transmitting HCV and by the frequency
of the exposure in the population. In the United States, the relative
importance of the two most efficient exposures associated with transmission
of HCV, blood transfusion and injecting drug use, has changed over time.
Blood transfusion, which accounted for a substantial proportion of HCV
infections acquired >1520 years ago, rarely accounts for recently acquired
infections. In contrast, injecting drug use consistently has accounted for a
substantial proportion of HCV infections and currently accounts for 60
percent of HCV transmission. The relative importance of other exposures has
changed little over time.
Unprotected sex with
an infected partner or with multiple partners has accounted for an estimated
15 percent of HCV infections. Although the role of sexual activity in the
transmission of HCV remains controversial, and the virus is inefficiently
spread in this manner, the relatively substantial contribution of sexual
exposures to the burden of disease can be explained by the fact that sexual
activity with multiple partners is a common behavior in the population and
that the large number of chronically infected persons provides multiple
opportunities for exposure.
In contrast to sexual
exposures, occupational and perinatal exposures contribute to a small
proportion overall of infections, and together with nosocomial or iatrogenic
exposures, they account for about 5 percent of HCV infections. HCV is not
transmitted efficiently through occupational exposure. The prevalence of HCV
infection among health care or public safety workers averages 13 percent
and has not been affected by changes or improvements in barrier precautions.
Transmission rates from HCV infected mothers to their infants average 5
percent or less, no associations have been demonstrated with mode of
delivery or type of feeding, and infants who acquire HCV infection at birth
may be less likely to develop chronic infection.
Thus, about 90
percent of HCV infections can be accounted for by known percutaneous or
mucosal exposures to blood. In the remaining 10 percent, no recognized
source for infection can be identified. Numerous studies have attempted to
identify additional risk factors for HCV infection. While case-control
studies of acute hepatitis C reported no association with tattooing,
acupuncture, ear piercing, military service, or foreign travel,
cross-sectional and prevalence studies of volunteer blood donors,
disease-specific clinic patients, and veterans receiving care in VA
hospitals have yielded conflicting results for some of these risk factors.
The lack of consistency among studies of highly selected groups for which
the temporal sequence of exposure relative to the disease was unknown is
cause for concern about the generalizability of such results.
Strategies for
reducing or eliminating the potential risk for transmission include: (1)
screening and testing of donors; (2) virus inactivation of plasma-derived
products; (3) risk reduction counseling and services; and (4) implementation
and maintenance of infection-control practices. Strategies for reducing
risks for chronic disease include: (1) identification, counseling, and
testing of at-risk persons; and (2) medical evaluation and management of
infected persons.
Health care
professionals in all patient care settings routinely should obtain a history
that inquires about blood transfusion, use of illegal drugs (injection and
non-injection) and evidence of high-risk sexual practices, such as multiple
sex partners or history of STDs. Primary prevention of illegal drug
injecting will eliminate the greatest risk factor for HCV infection in the
United States. Although consistent data are lacking regarding the extent to
which sexual activity contributes to HCV transmission, persons having
multiple sex partners are at risk of STDs such as HIV, HBV, syphilis,
gonorrhea, and chlamydia.
Testing should be
offered routinely to persons most likely to be infected with HCV, which
include persons who ever injected illegal drugs; received plasma-derived
products known to transmit HCV infection that were not treated to inactivate
viruses; received transfusions or solid organ transplants before July 1992;
and were long-term hemodialysis patients. Based on a recognized exposure,
testing also is indicated for health-care workers after needle sticks,
sharps, or mucosal exposures to HCV-positive blood and for children born to
HCV-positive women. Immune globulin and antiviral agents are not recommended
for post-exposure prophylaxis of hepatitis C.
HCV-positive persons
with a long-term steady partner do not need to change their sexual
practices; however, they should discuss with their partner the need for
counseling and testing, and the couple should be informed of available data
on risk for sexual transmission of HCV to assist them in making decisions
about precautions, including the low, but not absent, risk for transmission.
HCV-positive persons do not need to avoid pregnancy or breastfeeding, and
determining the need for cesarean delivery vs. vaginal delivery should not
be made on the basis of HCV infection status. There are no recommendations
for routine restriction of professional activities for HCV-infected
health-care workers, and persons should not be excluded from work, school,
play, child-care or other settings on the basis of their HCV infection
status.
References
- Centers
for Disease Control and Prevention. Recommendations for prevention and
control of hepatitis C virus (HCV) infection and HCV-related chronic
disease. MMWR 1998;47(No. RR-19):133.
- Alter MJ,
Kruszon-Moran D, Nainan OV, et al. Prevalence of hepatitis C virus
infection in the United States. N Engl J Med 1999;341:55662.
- Polish
LB, Tong MJ, Co RL, et al. Risk factors for hepatitis C virus infection
among health care personnel in a community hospital.
Am J Infect Control
1993;21:196200.
- Panlilio AL,
Shapiro CN, Schable CA, et al.
Serosurvey of human
immunodeficiency virus, hepatitis B virus, and hepatitis C virus
infection among hospital-based surgeons. J Am Coll Surg 1995;180:1624.
http://janis7hepc.com/hepatitis_c_research7.htm
Transfusions & Transplants
Currently, HCV is rarely
transmitted by blood transfusion. During 1985-1990, cases of
transfusion-associated non-A, non-B hepatitis declined by >50% because of
screening policies that excluded donors with human immunodeficiency virus
(HIV) infection and donors with surrogate markers for non-A, non-B
hepatitis. By 1990, risk for transfusion-associated HCV infection was
approximately 1.5% per recipient or approximately 0.2% per unit transfused.
During May 1990, routine testing of donors for evidence of HCV infection was
initiated, and during July 1992, more sensitive- multi-antigen- testing was
implemented, reducing further the risk for infection to 0.001% per unit
transfused ( i.e.,1 in 100,000 per unit transfused).
Current risk for transfusion-associated hepatitis C is
1/100,000 per unit transfused.
Receipt of clotting
factor concentrates prepared from plasma pools posed a high risk for HCV
infection until effective procedures to inactivate viruses, including HCV,
were introduced during 1985 (Factor VIII) and 1987 (Factor IX). Persons with
hemophilia who were treated with products before inactivation of those
products have prevalence rates of HCV infection as high as 90%. Although
plasma derivatives (e.g., albumin and immune globulin (IG) for intramuscular
(IM) administration) have not been associated with transmission of HCV
infection in the United States, intravenous (IV) IG that was not virally
inactivated was the source of one outbreak of hepatitis C during 1993-1994.
Since December 1994, all IG products - IV and IM- commercially available in
the United States must undergo an inactivation procedure or be negative for
HCV RNA (ribonucleic acid) before release.
Transplantation of organs
(e.g., heart, kidney, or liver) from infectious donors to the organ
recipient also carried a high risk for transmitting HCV infection before
donor screening. Limited studies of recipients of transplanted tissue have
implicated transmission of HCV only from nonirradiated bone tissue of
unscreened donors. As with blood donor screening, use of anti-HCV (antibody
to hepatitis C virus)- negative organ and tissue donors has virtually
eliminated risks for HCV transmission from transplantation
http://www.cdc.gov/ncidod/diseases/hepatitis/c_training/edu/1/epidem-trans-2.htm
Methods of transmission
Several activities and practices have been identified
as potential sources of exposure to the hepatitis C
virus. Anyone who may have been exposed to HCV through
one or more of these routes should be screened for
hepatitis C.
- Injection drug use
Those who currently or have used
drug injection as their delivery route for illicit
drugs are at increased risk for getting hepatitis C
because they may be sharing needles or other
drug paraphernalia (includes cookers, cotton,
spoons, water, etc.), which may be contaminated with HCV-infected
blood. An estimated 60% to 80% of all IV drug users in
the United States have been infected with HCV.
Harm reduction strategies are encouraged in many
countries to reduce the spread of hepatitis C, through
education, provision of clean needles and syringes, and
safer injecting techniques.
- Drug use by nasal inhalation (Drugs which are
"snorted")
Researchers have suggested that the transmission of
HCV may be possible through the nasal inhalation (insuffulation)
of illegal drugs such as cocaine and crystal
methamphetamine when straws (containing even trace
amounts of mucus and blood) are shared among users.[12]
- Blood products
Blood transfusion, blood products, or
organ transplantation prior to implementation of HCV
screening (in the U.S., this would refer to procedures
prior to 1992) is a decreasing risk factor for hepatitis
C.
The virus was first isolated in 1989 and reliable
tests to screen for the virus were not available until
1992. Therefore, those who received blood or blood
products prior to the implementation of screening the
blood supply for HCV may have been exposed to the virus.
Blood products include clotting factors (taken by
hemophiliacs), immunoglobulin, Rhogam, platelets,
and plasma. In 2001, the Centers for Disease Control and
Prevention reported that the risk of HCV infection from
a unit of transfused blood in the United States is less
than one per million transfused units.
- Iatrogenic medical or dental exposure
People can be exposed to HCV via inadequately or
improperly sterilized medical or dental equipment.
Equipment that may harbor contaminated blood if
improperly sterilized includes needles or syringes,
hemodialysis equipment, oral hygiene instruments, and
jet air guns, etc. Scrupulous use of appropriate
sterilization techniques and proper disposal of used
equipment can reduce the risk of iatrogenic exposure to
HCV to virtually zero.
- Occupational exposure to blood
Medical and dental personnel, first responders (e.g.,
firefighters, paramedics, emergency medical technicians,
law enforcement officers), and military combat personnel
can be exposed to HCV through accidental exposure to
blood through accidental needlesticks or blood spatter
to the eyes or open wounds. Universal precautions to
protect against such accidental exposures significantly
reduce the risk of exposure to HCV.
- Recreational exposure to blood
Contact sports and other activities, such as "slam
dancing" that may result in accidental blood-to-blood
exposure are potential sources of exposure to HCV.
- Sexual exposure to blood
Sexual transmission of HCV is considered to be rare.
The CDC does not recommend the use of condoms between
discordant couples (where one partner is positive and
the other is negative); however, because of the high
prevalence of hepatitis C, this small risk may translate
into a non-trivial number of cases transmitted by sexual
routes. Vaginal penetrative sex is believed to have a
lower risk of transmission than sexual practices that
involve higher levels of trauma to anogenital mucosa
(anal penetrative sex, fisting, use of sex toys).[13]
- Body piercings and tattoos
Tattooing dyes, ink pots, stylets and piercing
implements can transmit HCV-infected blood from one
person to another if proper sterilization techniques are
not followed. Tattoos or piercings performed before the
mid 1980s, "underground," or non-professionally are of
particular concern since sterile techniques in such
settings may have been or be insufficient to prevent
disease.
- Shared personal care items
Personal care items such as razors, toothbrushes,
cuticle scissors, and other manicuring or pedicuring
equipment can easily be contaminated with blood. Sharing
such items can potentially lead to exposure to HCV.
HCV is not spread through casual contact such
as hugging, kissing, or sharing eating or cooking
utensils.
Vertical transmission
Vertical transmission refers to the transmission of
a communicable disease from an infected mother to her
child during the birth process. Mother-to-child
transmission of hepatitis C has been well described, but
occurs relatively infrequently. Transmission occurs only
among women who are HCV RNA positive at the time of
delivery; the risk of transmission in this setting is
approximately 6 out of 100. Among women who are both HCV
and HIV positive at the time of delivery, the risk of
HCV is increased to approximately 25 out of 100.
The risk of vertical transmission of HCV does not
appear to be associated with method of delivery or
breast feeding.
http://en.wikipedia.org/wiki/Hepatitis_C
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